Yes, the beta is likely to be announced this weekend/early next week. Usually a bunch of us install it and then do our best to break it.
Meanwhile, we submit problems that we find to http://moodle.org/bugs
. To play it safe, you should count on another week or so after that for the official/stable version to come out. It might be sooner (I'm sure the developers wish that)--or it might take longer depending on what testers find.
You should feel comfortable creating some classes now and beginning to add activities
(in whatever version of Moodle you are using). All of your information will be upgraded when you install the newer version of Moodle. In the meanwhile, your chats will be groupless, but after the update you can rearrange them.
At this stage, the group stuff (which is really, really cool), is part of most of the modules. Many of us have already been testing it out with very few problems. The way that we've sneek-peeked at the code is through the latest nightly and CVS, these are two ways to look at/install developmental code. But a key guide-rule is to avoid puting any code onto a production site (one with ongoing classes) until it has been tested as beta code and then is considered stable for release. The best times to update, then, would be at every stable release (1.0, 1.1, future 1.2).
I hope this helps.