the best way to contribute is to create a tracker issue and attach your patch - then post here in the forums about the patch and get people to vote on it...
Make sure it applies cleanly against the latest master code (not 1.9 or 2.0) and it's more likely to be reviewed.
Also check out some of the other patches in the tracker for ims - if your patch applies cleanly on top of these or duplicates some of the functionality make sure you link the tracker issues by posting the bug numbers in the comments.