Can the hard drive in an Apple TV be upgraded? How? I own an Apple TV, with 160GB of internal storage.  I'm interested in replacing that hard drive with a larger one, perhaps 640GB, or else the largest 2.5" drive I can get that would be compatible.

Is it possible to replace the internal hard drive in an Apple TV, i.e. DIY?

If so, how, or where can I find more information?

Any tips about the challenges I will need to overcome: e.g. opening the device, copying old drive contents over, etc.?

Thanks!

p.s. I don't care about my warranty; it's long gone.
Yes, you can. Good thing you don't care about your warranty though. Engadget published an article about it with instructions some time ago.