teleconferencing solutions for nonprofits

I'm currently looking into various affordable teleconferencing solutions, and I'd be curious as to what other ones people have started using in nonprofits environments.

Right now, I use Arkadin for work and FreeConferenceCalls.com for personal consulting stuff.  I recently stumbled across Foonz and have been impressed with what little I've seen there.

Arkadin (a pay service) has a private and public PIN. None of the free conference solutions I've used have had private PINs, just public ones where particupants hit, say, 12345# and the moderator hits 12345*.

Foonz.com is an interesting concept.  You call a number, type in your group number, and then it autocontacts all the people in that group. I like the concept, and I'm curious now if anyone has rolled their own solution with a tool like Asterisk, Trixbox, or FreePBX.

Any other suggestions?

(Here is a link to all sorts of cool free VoIP solutions, for those new to the subject)

I use ReadyTalk for many of our conference calls. It's not free, but it is available on TechSoup. This is also the platform we use for our webinars, though I often only use the teleconference part of it. I've found it to work better than Skype for bigger calls with more than 3 attendees, as more than one person can talk at once. However, we've had trouble getting a lot of interference with other lines, so often times each person must mute their line until they speak to cut down on this (hence, eliminating a lot of the mentioned advantage).

What would be the benefit of having a private vs public pin as in Arkadin? Trying to get my head around how you could use this feature.

Foonz looks really cool. In particular, I like that it will also allow you to send a text message to everyone in the group, so folks can easily dial-in from a mobile number. Also you can leave a group voicemail. That would come in handy especially for when a meeting is cancelled and/or location or other details change. And the (free) price is right!

All excellent, thank you!  But am I missing any mention of true VIDEO conferencing tools? One of the boards I serve has a state-wide footprint, and they wanted to explore the possibility of using Skype specifically for video-conferencing. I will be experimenting with it, but I'm not yet certain that we can do multiple-party video-conferencing via Skype. And I don't want to ask the board to download it and try it if we're not going to keep it.