It's not very active these days, but there is a Yahoogroup dedicated to PSK and other digi modes on VHF and UHF : http://groups.yahoo.com/group/PSK_VHF_UHF_HAMRADIO/
144.150 USB was the frequency most used for PSK. Recommended frequencies of the other common VHF/UHF modes will be found on the website, as well.
Overall, we found that PSK was too sensitive to multipath on VHF, and multipath is very common. Still, I checked into the net run by KB9UMT on 2 meters every week - a distance of about 300 miles from here in SE Minnesota to his QTH near Peoria. MFSK actually worked better.
A lot of folks are playing with the NBEMS suite of protocols for FM, and on VHF/UHF they tend to use MT-63/2000 over FM. This mode is pretty tolerant of different audio levels, so you can actually do it without an interface - just play the speaker from the computer into the mike on your HT or VHF FM rig, and vice-versa. With the HT just sitting net to a computer, it works pretty well, usually. We have a weekly VHF net on 2 meters up here, and it's also on Reflector 9627 for IRLP. The net is at 9 p.m. Central time.
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