how do i make a nandroid backup? is it in the market?
If you have ROM Manager and you use Clockwork (that specific combination), you can open ROM Manager and choose the option to backup your current ROM. That will reboot the phone into recovery, and proceed to create a nandroid backup.
It's a good idea to learn how to do things manually in recovery, though. You have no choice if you use Amon RA recovery.
You can use ROM Manager to reboot into recovery directly, or turn the phone off, then turn it back on while pressing and holding the volume down button. That will take you to hboot, where you can choose the option to reboot into recovery. You use the volume buttons and the power button in recovery to navigate/select options.
Clockwork Recovery - Once in recovery, select the nandroid menu option, then select backup.
RA Recovery - Select the menu option for backup/restore, then backup.
Nandroid backups are stored as img files for each partition that is backed up. You can see where using a file manager of your choice.
Clockwork - /sdcard/clockwork/
RA - /sdcard/nandroid/(unique number)/
Each nandroid backup is stored in a directory under either of the above directories named after the date/time GMT that it was created.