I haven’t done independent research, so I’m not claiming I know one way or another. And I understand that Snopes is not everyone’s cup of tea. That being said, Snopes indicates that Obama was not registered as a foreign student at Occidental:
http://www.snopes.com/politics/obama/birthers/occidental.asp
Snopes is as trustworthy as wikipedia. I would take any of their claims with a grain of salt.
Snopes is as useful as Faactcheck. Run by self admitted liberals.
For political stuff, it’s worse than useless. Anyone can google just like they do.