Personally i don't have any experience with 2 screens, so...

Atm I'm running 4 clints on 22" widescreen. Going to add a 5th from my main account later, but no way i'm going to cram 5 clients on 1 screen. As I'm running XP, what happens with the resolutions on horizontal span? Needs to be same? So do I need to get a widescreen atleast if not the same size?