This is a tutorial on how to install an unofficial version of CyanogenMod 9 for the Galaxy Tab 2 7.0. CyanogenMod 9 is not currently supported by the CyanogenMod team, but the beauty of open source is that developers can port it to any device they want.
This is the first build of CM9 for the Galaxy Tab 2 7.0, so you can expect some bugs. The known bugs include audio input not working, Bluetooth not being able to send audio, and Chrome Beta not being supported.
Step 1: Install ClockworkMod recovery.
Step 2: Download the ROM and Google Apps zip onto your Galaxy Tab 2 7.0. Check this post for updated versions of each of those links
Step 3: Boot into recovery.
Step 4: Select backup and restore and create a backup. Navigate with the volume buttons and select with power button.
Step 5: After the backup select wipe data/factory reset.
Step 6: Select wipe cache partition.
Step 7: Select advanced and Wipe Dalvik Cache.
Step 8: Select install zip from sdcard, choose zip from sdcard, and find the ROM that you downloaded.
Step 9: Then do the same thing but for the Google Apps file that you downloaded.
That is all you have to do to install CM9 on your Galaxy Tab 2 7.0. If anything goes wrong, then just restore your backup from ClockworkMod.
Source: Rootz Wiki