Dashwire is a great concept for Windows Mobile devices (well its a great concept for any phone really) but currently only works on WM and Symbian powered Nokia devices.
The short description is: Dashwire gives you access to your phone through a web browser.
It works by installing a client application on your phone which then uses whatever data connection it has available to send and receive information to the DashWire servers.
Once you're synced you can view all of you contacts, pictures, sms messages, etc that are on your phone right from the web interface - and it works great. You can also respond to SMS messages from your web browser and they'll be sent out from your phone without any additional steps.
Its a product I haven't used enough but I've recently become a fan again since I've set up my phone to use WiFi at home. I've also heard from one of the company's founders that they've got some killer new features coming out soon so keep an eye on the website.
Take a look and sign up here: