Ok... pull the battery out for 30 seconds... put it back in... press and hold the Volume Down button, then press and hold the Power button, hold both for about 5 seconds, then let go of the power and then the volume... you should come up in hBoot... select Recovery and go from there.
FYI=the first time i loaded CM7 (maybe CM6) on my brothers dINC, it got stuck there for 20 minutes
i loaded CM7 on my TB a few days ago & it loaded up in about 3 minutes---if it's the first time you're flashing it, don't freak out if it takes a bit of time. even if it looks like it's getting hung up on the boot animation--let it do its thing before doing anything drastic
1-10 minutes is usual for a 1st ROM-Flashing load time
11-15 is pushing it but still possible depending on the elements of the ROM
20 is when i jump back into recovery