I would hold on to the original SIM card. Some people have had issues that if they restore it without a SIM card, they cant get it out of the Plug Into ITunes Mode until they put the original SIM card in (even if its not active).
http://blog.iphone-dev.org/post/1160213613/redsn0wier jailbreak is out for Mac users for 4.1 we are still waiting for PC’s
Phone won’t boot without the SIM card will it? I mean not to a usable state?
it will but sometimes if you dont have a sim in it when it connects to itunes it thinks the phone isnt activated. any old At&t sim card works… so better to just leave a old on in there
The iPhone will boot without it into a usable state as an iPod. The only times you may run into problems is after you update/restore it may try to activate itself out of the recovery mode and sometimes you need to put the SIM card in for that.
Can someone give me the current low down of tethering?
I have a JB 3gs on 4.0.1
I use MyWi out of Cydia. It allows USB and also turning the iPhone into a hotspot. I use it sometimes sitting in airports playing poker, browsing the news. My data usage a month is about 4-6GB and I haven’t had any heat from ATT.
Jailbreak with JailBreakMe.com (if you have not already) And purchase TeatherMe from Cydia. Its $4.99, and enables native tethering. MyWi is $20, hard to steal, caused issues when I attempted to crack it, and is inefficient. Its really nice how it creates a WiFi network to connect to though. The native tethering is EXTREMELY efficient, but only works over USB (to a computer with iTunes installed) or bluetooth. You should be able to have the phone sitting there with the screen off, and tether it over Bluetooth for several hours before killing the battery. Obviously USB would run forever, if you have a cable with you. Speeds are about the same via all methods.
I use 10-30 GB a month, for years, and ATT never said shit.
The MyWi crack works fine. you just gotta follow the directions with installing the original, removing it, installing the crack, removing rock, then launching it. I use it constantly and was not paying $20 for that app. Lol. Screen can go off and everything and USB makes it great for battery like you said. 10-30GB a month is intense. The most I have had was 15GB when my internet at home sucked and used to stream XM a lot. Now with my decent internet at home and not using XM, I cut that in half since WiFi is on so much more.
I was using Rock for My3G that was legally purchased, since it was only $2.79 at the time. I even tried removing Rock and using a cracked My3G, but it wasnt working for some reason. But $20 is kinda insulting to pay for a little button on my phone I rarely use. I get 2-3x longer runtimes with native tethering over wifi tethering of MyWi, even with the transmit power down to 30%. It works quite well, but it has a few quirks and isnt as simple and easy as native tethering.
Im just waiting for the new 4.7.7 Cydia version to have a crack that works with people who ran out of the 3 day trial. I have the Elpelle6 crack, but it only works when I set my phones date to 9/13/10 and reboot… Since thats when I started the 3 day trial. 
Currently everything on my phone is legit, and its only jailbroken for a few tweaks and My3G. No facetime over 3G, 20MB app limits, etc… Thats unacceptable. I dont use WiFi, dont sync my phone to my computer, and dont want to be limited. The vast majority of my data use comes from downloading podcasts in Podcaster from the app store. Every few days I run it overnight to keep my podcasts updated… And most of them are 400-600MB. ATT dosent say shit, since they know its far too easy to use massive data without tethering. My brother usually uses 10GB a month, and even my dad averages several GB.
I really dont understand how people manage with a 2GB plan, youd be scared to use it, and be forced to use WiFi…
Btw this is 3g and iPod Touch 2G only.
The jailbreak for 4.1 is out. Geohot released his tool limera1n.com at Saturday and the Chronic Dev Team released theirs yesterday.
LimeRa1n is similar to the purplera1n for the older devices. Some of the newer 3GS boot ROMS dont work right or buggy but I ran it on 3 iPhone 4’s and all installed Cydia from the LimeRa1n app.
If you are using an Unlock, there is no working crash found for the baseband so do not use this and wait for the PwnageTool or use Umbrella to save your baseband version.
I was out of town this weekend and saw the jailbreaks were coming out. Figured I’d look into it tonight.
Running 4.0.1 right now, jailbreakme.com jailbroken and my SHSH is backed up. Assuming I just let itunes upgrade me to 4.1 then run the latest jailbreak or is there a better way?
Where’s the jailbreakme.com update for 4.1? 
Thats what I was and did. SHSH blobs are just for if you wanted to downgrade back to 4.0.1. Let iTunes upgrade to 4.1 and then download linera1n and it was pretty simple. You get the limera1n app on your home screen, install cydia from it, then uninstall limera1n.
Lol I wish there was another userland exploit out there but the tools use a boot rom which is good for the future jailbreaks 
And Apple TV. This one is gonna be tougher to patch up than the PDF exploit
Upgraded to 4.1 and did the jailbreak last night. Used greenpi0son instead of limerain and it went smooth. As soon as I was done used umbrella to backup my 4.1 blobs so now I can downgrade to 4.0.1 or 4.1 if I ever need to.
Your blobs from 4.0.1 will allow you to downgrade. 4.1 blobs only will allow you to restore to 4.1 if Apple stops signing 4.1 blobs when 4.2 is out.
Yep, exactly.
The point being you should always backup those blobs so you have downgrade options. It’s very easy to mistakenly accept an update and if you don’t have the blobs backed up you’re screwed.
Finally did this on limera1n.com. Went smooth the second time because I accidentally closed it halfway through the first time and had to restore. F.
Now I can’t remember how to get installous. lol