I just bought this Samsung netbook to use on campus after giving my laptop to my parents since I hardly ever used it. I obviously do most everything on my desktop but this netbook is pretty convenient.

http://www.bestbuy.com/site/Samsung+-+N ... Id=1944065

My question is if I put a full OS on it like XP or 7 instead of the stupid Windows 7 Starter that it comes with, will I be able to put 3GB of RAM instead of the Starter max of 2GB?

There will probably be two potential issues here. 1) Whether the hardware will support that much ram as netbook hardware can be different and 2) whether the OS will recognize it. The OS should recognize the extra ram fine as long as the hardware can support it. You might look into whether or not XP (or full blown Win 7) will actually load and find the necessary drivers.

Based on what I just found online, that netbook will only support a maximum of 2GB. I'm guessing this is because it has a single slot for RAM modules.

You might be able to use a 4GB stick, if they exist in a netbook form factor. You'll want to find out for sure if it would even work, though.