Foldershare - this is cool
I've been using Foldershare for a few days just to sync a few files between work and home and my initial impression is that it's really cool!
I set up a single directory on my computers to sync, put some files into them and watched as they were syncronized in the background (and its fast). I've currently got ~430 files syncing between the two computers.
The really nice thing is that I can use the website (once logged in) to search either computer for files. Foldershare integrates with MSN Desktop Search, so when you do a search, you get email, files or anything on your computer, complete with abstracts (very cool).
In additon, you can browse your entire file system on either computer using the website and retrieve files as needed.
You can even do it from your mobile device - just go to the website, log in and grab that power point press and email it to a client from the coffee shop with out having to go back to the office to your computer.
If you have a folder shared, you can also share it with a friend (they need to install the software - which is free), so they can sync it too.
The software is very lightweight - unlike groove (which is very cool and has lots of functionality, but is lots heavier) and doesn't have an annoying splashscreen or startup delay.