The problem with Kinkos is that I live in a rural area of Georgia and there is no Kinkos out here. I often do depos in my home office or dining room for people from out of state who want to depose Monrovians (People from Monroe, GA). I lost a very good job because I was not set up for videoconferencing.
I will try the websites you listed.
(I have done depos at Kinkos in other metro areas and it is a nice place to do it.)
If you have a conference room all you need is a computer, web cam and DimDim, oovoo or even skype as previously mentioned.
make sure you get a good professional looking webcam so your clients wont feel that they are sitting at their kids laptop at home.
Use a good big screen as the output (not your laptop)
Also, dont forget to get 3 good table Mics and a mixer.
If you do the above you will have a system that rivals that of kinkos.
Your cost shouldn't exceed $300 (assuming you have a nice TV screen)
P.S: You MUST have a good internet connection 1/2+ MB Per Sec.
I had a client come in from another state once that wanted to attend via a Skype connection. His client ended up nixing the Skype appearance so he ended up showing up personally. But he said he'd done it that way before and was pleased with the outcome.
As Monti says, you need a good Internet connection, and not an air card. I looked into it at one time (besides the Skype thing) and it all boiled down to a good hard-wired connection.
And Regus is HORRIBLY expensive. You get no deals with Regus. If it cancels within 24 before the depo is supposed to start, you still have to pay them, 100%. I learned that the hard way on an all-day depo ($400+ down the drain! Except I learned never to use Regus again.)