What do you use/do to stay in touch with business partners that are in a different geographical location?

I'm looking for a good way to stay in touch with the hosts of my Momtrepreneur Exchanges around the country. There's a host in each of our 23 cities so far. It's a pile of people in different time zones...anyone have a method or program that is effective for them?

I work for a tech company with branches at Mexico, BRazil, Japan and China.
We use skype/msn for short communications and with few people at the same time. If the meeting is going to be longer or more people is involved we use webex to share a "board", PPTs, etc.
We have an internal wiki too to share information too.

IM works great for one-on-one. If you need to conference all, maybe Skype, but I'm not sure what the max limit is in it. These are free tools. If you're all in different time zones, some sort of bulletin board accessible only by the members would probably be great; that way each can chime in any time they have time, especially moms...

We have an IRC chat room that is always on and it is what we use for most daily conversations. We also Skype, DimDim, GoToMeeting, and email, but I would estimate 75% of our communication goes through IRC.

My company, while virtual, is smaller than that...however the open source projects I'm involved with are not. What we've found works best is:

• An IRC channel or MUC room.
• IRC /msg or Jabber
• An issue tracker
• Email discussion list, private NNTP server/group, or web forum
• Some sort of web space to stick documents and info everyone should have available for reference.

It sounds like a long list, I know, but the more tightly integrated it is the easier it becomes to use. For example, a service like GitHub can give you a private repo with a rudimentary issue tracker, a nice revision-controlled Wiki, getting you halfway there. Things like Active Collab or Open Atrium give you many of these tools in one place, too.

Important characteristics of what I have suggested:

• I always focus on text-based communication because it is loggable, and it scales well. I can search for things I missed/forgot, or to get clarification about what was said on a topic, at any time. Also, I can carry on multiple conversations at once without losing track of any of it.
• There should be a central place to follow action items so everyone stays on task.
• It should be easy to reach an individual or the group via synchronous (instant) or asynchronous (when they check their inbox) communication.
• I choose open protocols/formats/apis wherever possible -- I like people to be able to choose their own clients so that following what's going on is as quick and convenient a part of their overall workflow as possible. The easier it is, the more people will actually use it.