I've been a happy Thunderbird user for the last year, but I'm really starting to get frustrated with it's lack of connectivity to other contact repositories like cell phones and PDAs.

I picked up a Dell Axim X51v last week, and have a Motorola E815 cell phone. Both sync seamlessly with the Outlook contacts, but neither can sync with Thunderbird's contact list.

As much as I love Thunderbird's flexibility, searching, and extensibility, it just doesn't help in keeping my stuff in sync.

Any ideas for a solution that doesn't involve returning to Outlook?