Collaborating in a global startup

As my website team has been growing, we've been wondering what's the best (and cheapest) way of keeping in touch with each other. We definitely don't want to spend on getting a facility for our team. We'd rather people work from home, and keep in touch online.

Here's a sum up of the tools we use (in no particular order) to get together and collaborate. Note, all tools are very usable in their free versions:

1. Google Apps:

Google Apps is the single most important collaboration tool for us..
Apart from setting up free email (yes, 7gigs and 99.9% uptime are good enough for us, thank you) with all the gmail features, we also get google docs, google talk with chat, calendars and https connectivity for security.
Google sites is another feature that adds in another level of sharing, but we haven't got to that level yet.

2. Skype:

Skype allows us to communicate with each other over a secure channel - whether it is voice or chat.
Skype also gives inexpensive communication options - such as unlimited US and Canada dialing and your own incoming number with voicemail - for under ten bucks a month (there's another application called MagicJack which claims $20 for the whole year - but we haven't tried that out yet).
Skype is also widely used by freelancers, so it is an invaluable tool to communicate with your team and freelancers.
If you would rather not get tied to your computer with a headset, there are excellent phones like this one from linksys, which give you crystal clear communication, by connecting with your router lan cable directly.
Skype also has options of auto-forwarding to your cell phone, and conferencing, which are invaluable.
Last up, you can pay for some packages, which allow you to have a phone answering system setup on skype.

3. Projjex
Given the high costs of using MS Project, and the fact that its not really collaboration friendly unless everyone has the app on their computer, Projjex was an excellent option for us. Though I dearly miss the Gantt Chart, which I can't seem to get here, projjex allows you to track your projects to completion and has a great, easy to use interface.
In your project meetings, everyone can login to their projjex account and will know what you're talking about. Also there are reminders and advanced project tracking features there.

4. Dimdim
Oh dimdim! The best thing since sliced bread I think!
Dimdim will give you free online meetings - get people onto a desktop share, do a whiteboard together or surf the internet together. Also you have presentations and online chat.
Better still, you get a free dial-in number to conference in your listeners and have a dialogue.
Multi-party webcam is also possible, though we weren't that keen on seeing how each of us are dressed during our meetings!

Dimdim is still being developed, but is relatively stable.
We did have a concern that you can't hear people signing in and out of the call, which brings up confidentiality questions.
I have also identified another free conferencing system that looks promising: Free Conference Call

Well these were some of the great tools I came across - all free. These have greatly added to our team being in regular touch with each other.

Do you have some other tools to share?