Section 1252. Operating motorcycles on roadways laned for traffic.
(a) All motorcycles are entitled to full use of a lane and no motor vehicle or motorcycle shall be driven in such a manner as to deprive any motorcycle of the full use of a lane. However, this subsection shall not be construed to prevent motorcycles from being operated two abreast in a single lane.
(b) The operator of a motorcycle shall not overtake and pass in the same lane occupied by the vehicle being overtaken.
(c) No person shall operate a motorcycle between lanes of traffic or between adjacent lines or rows of vehicles.
(d) Motorcycles shall not be operated more than two abreast in a single lane
(e) Subsections (b) and (c) shall not apply to police officers in the performance of their official duties.
http://www.nysgtsc.state.ny.us/mcyc-vt.htm#sec1250
I got this from the NY DMV site. I know that in California “lane splitting” is “legal”, but definately not recommended.