Important Note: SyncKolab relies on a lot of Thunderbird internals in order to work. This means that on every version upgrade of Thunderbird, there is quite a chance that it will break. Please use bugzilla to report such an issue (after checking if it hasn't been reported already).
SyncKolab is a Thunderbird extension allowing to synchronize your contacts, calendar items and events using IMAP.
For more information please refer to the main page
You can always checkout the current nightly if you run into major problems (like having no configuration options available) - since they are most often fixed there.
Make sure to read http://www.gargan.org/en/Mozilla_Extensions/SyncKolab/FAQ/
For Bugs please check out Mozdev Bugzilla:
If you want to help out you can use ant to build a packe once you checked out the code (just run 'ant' in the folder and it will create an xpi file).
You can also run all tests using 'ant test'