It is not full speed but for many games (especially RPGs) it is close enough. There is also some frame skipping, but usually not that noticable unless you specifically look for it. It can cause problems with things like Mother 3's timed hits where you have to press A in time with the music. As for the fastest place, I have always used realhotstuff.com. They ship via USPS first class from New Jersey.
Update- Forgot to add, be sure to get version 1.21 of the emulator and get the latest game_config.txt file for it. If you use the latest, 1.30, you won't be able to use game_config.txt and quite a few games (like Pokemon) won't work as well or at all.