Description:
Here it is, the brand new foursquare client for Windows Phone. My square have both free and premium versions.

Fell free to write comments, sugestions, bug reports, etc.

Features:
- Use your location to find out nearby places.
- See your friends latest check-ins.
- View tips of places.
- Explore foursquare and earn points and badges.
- Use even gps or network fix.
- Integrated with google maps.

System Requirements:
- Operating System: Windows® Phone (Mobile) with version 6.0 or higher.
- Device: Your phone must have a touch display.
- Compatible display resolutions: QVGA, WQVGA, VGA, WVGA.
- .NET CF v3.5.

Note to CDMA people:
Location may be a bit imprecise when gps is not fix.

Notes:
- This app may use your data plan if not using wifi.
- The phone radio must be ON in order to locate you.

More screenshots, information and F.A.Q. here.
If you like this project, please consider donate to the developer.

Update Description:
v1.3 beta 3 (03-10-2010):
- Add a user as friend.
- Improved badges list.
- Show mayorship status on checkin result.
- Show scores on check in result.
- Fix: search hitting enter key.
- GPS improvements, signal strength indicator.
- Satellite, terrain, hybrid modes for maps.
- Ping notifications (note: pings does not use gps, cell id, etc.).
- View full-sized user avatar.
- Turn off gps to save battery after 5 minutes on background.
- Fix: avoid cached files to be scanned by picture apps.
- The leaderboard.
- Show foursquare error messages.
- Shout without venue.
- Improved app icon.
- Tips nearby.
- Fix: check in with GPS.
- Fix: any post with "&".
- Fix: interface sometimes gets stuck when no internet.
- Fix: post with special chars, accents and umlauts.
- Fix: keyboard deploy.
- Link to 4sq web profile for a user.

v1.2 Beta 2 (09-08-2010):
- General fixes, crashes, etc.
- CDMA support, geoip added as a fallback.
- GPS fixes on places and friend list.
- Fix on create new venue (tap to fill address).
- Fix on premium account. Validation.
- GPS icon.

v1.0.3865.26913 Beta:
- Fix: clear shout message.
- Fix: version display on about.
- Premium services.
- Adservice improved.
- Check for updates.
- Show specials on place list.
- Adjusting nearby,favorites,etc place list.

Alpha2:
- Fix: maps.
- Fix: memory, image drawings.
- Other general fixes.
- Accept and refuse friend requests.

Alpha1:
- Initial release.
- Friends, places, settings and about tab.
- Maps, adservice.