I'm testing out the new Nokia 5300 XpressMusic for T-Mobile right now, and was dismayed to find that it wouldn't sync with my Mac's Address Book and iCal applications. However, a quick Google search yielded an easy hack that I successfully employed with the 5300, and that looks to work with other unsupported Nokia handsets as well.
The fix takes about five minutes (or less) and involves digging into one of iSync's resources, cutting and pasting some text, and dragging and dropping a single graphic file. If you can cook from a recipe you can complete this hack, whether or not you think yourself "tech savvy." And it works - or at least it did on my MacBook with the aforementioned 5300! I just synched my contacts and calendar information over Bluetooth.
Mac users, check it out: tumblr.matschaffer.com/post/167518