I’m using the terrific-looking Basecamp for collaboration for a really, REALLY cool project I’m starting work on. (Details later once I get a contract actually in hand.) One of Basecamp’s nifty features is an iCalendar feed, which lets you track milestones by subscribing to a feed.
The only hitch is that Outlook doesn’t support iCalendar subscriptions (which have been around for years but won’t get wrapped in until Office 12). However, some smart folks tossed together RemoteCalendars on SourceForge which is a COM plugin enabling iCalendar subscriptions. There are versions for .NET 2.0 and 1.1 Frameworks. I had no luck with the 2.0 version, but there’s a workaround version for 1.1 here.
This is way slick because I can automatically update my Outlook from my Basecamp, then get all those milestones on my Treo 650. I’m lovin’ it.