Tech Blog - Here is a quick howto on upgrading Samsung Galaxy Tab 7 from Android Froyo 2.2 to Gingerbread 2.3 using Samsung Kies.
Step 1 - Install Samsung Kies and follow the onscreen instruction, you can download latest version from their Samsung website
Step 2 - Once installed plug in your Samsung Galaxy Tab 7 P1000 to your PC USB port, make sure your Samsung Galaxy Tab 7 is fully charge
Step 3 - Kies will automatically auto detect your Samsung Galaxy Tab 7, and ask if you want to upgrade, it will ask you if you also want to backup if click you click Yes.
Step 4 - After step 3 it will update the firmware on your Samsung Galaxy Tab, wait till its done, make sure do not disconnect the cable during update, once done you can disconnect and check your Galaxy Tab.
Note: The firmware doesn't delete or wipe anything of your Samsung Galaxy Tab, however if your are rooted it will unroot it, the only way to root Samsung Galaxy Tab 7 Gingerbread is to use Cf-Root