I thought that I would do a tutorial on how I export footage from Adobe Premiere to Vimeo. With every new version of Premiere the process slightly changes. This tutorial shows you how to export using Premiere CS5 or CS5.5. Remember these are my opinions and what works best for me.
The main thing when you are exporting is to make sure that you match your sequence settings with your export settings. If you shot in a frame rate of 23.976 then you need to make sure to export in a frame rate of 23.976. This is also the case for frame size as well as aspect ratio.
I use the h.264 codec with constant bitrate of 9mbps. Vimeo prefers the h.264 codec and recommends a 5-6mbps bitrate. That is fine for standard definition footage but for high definition footage, I recommend a 9mbps or higher bitrate. The thing to remember is that Vimeo is going to re-transcode your footage, so why not give them a better quality export to start with.