You will need to connect the iPad to the computer that you normally sync to and you should then be able to reset the iPad and restore/re-sync your content to it (http://support.apple.com/kb/HT1212) - you may need to put the iPad into recovery mode in order to be able to reset it : http://support.apple.com/kb/ht1808
If you do it via a different computer then :
If you restore on a different computer that was never synced with the device, you will be able to unlock the device for use and remove the passcode, but your data will not be present.