How to MMS messaging on Nokia 900
The Nokia N900 brings the power of computer to mobile devices. It’s a high performance mobile computer with advanced Maemo 5 software on Linux.
          This recent mobile phones range medium-high which have been launched to the market does not support MMS (multimedia messaging), here is a guide for all users who wish to send a mms with nokia.
1. Install fAPN to add GPRS APN, since n900 will only allow you to add wifi. 
            2. Open fAPN
            3. Hit add new APN
            4. Enter desired name then hit add
            5. Go to settings
            6. Internet Connections
            7. Connections
            8. Highlight the new APN then hit edit then next
            9. Access point name: wap.voicestream.com and leave the rest blank
            10. Hit next
            11. Hit advanced
            12. Use proxy: true 
            HTTP proxy: 216.155.165.50
            Port number: 8080
            Automatic configuration: true
            Web address: http://mms.msg.eng.t-mobile.com/mms/wapenc
            13. Hit save then finish
            14. Then I installed fMMS
            15. Open fMMS
            16.APN: choose the one that you just added
            MMSC: http://216.155.174.84/servlets/mms
            Resize image width: 300
            Your phone number: your own phone number
          17. Hit save.
 
Nokia N900: Full fMMS (0.6/0.7) Walkthrough - Send & Receive