My brother just got a Wii and gave me his 360. Where do I start with modding/flashing this thing?
How can I backup my games onto my 360 hdd via the 360's dvd rom?
I really dont play on XBL that much, I am not sure if that makes a difference.
Can I get my old xbox games onto my 360 and play them (i.e. scarface)?
Also can I play all of the old NES and SNES games on 360?
Where do I start with modding/flashing this thing?
Read some guides to find out which drive it has, then read some tutorials on flashing it.
How can I backup my games onto my 360 hdd via the 360's dvd rom?
You Can't
I really dont play on XBL that much, I am not sure if that makes a difference.
Yes, it makes a difference because if you mod your system there is a chance that you can get banned from live.
Can I get my old xbox games onto my 360 and play them (i.e. scarface)?
They have a list online called "backwards compatibility" and if the game is on that list you can play it on your 360. But if you also have an Xbox then i would use that instead. You will get no improvements playing it on the 360.
Also can I play all of the old NES and SNES games on 360?
Yeah, If you feel like paying for every game. It is not like the older Xbox which could do way more as a console. You can not play games from the hard drive uless you paid for and downloaded it off the Xbox Live Marketplace. Same goes for the older games. They charge you for each one, you have to download it, then you can play it. Again, this is a feature best left to your original Xbox as there are a ton of emulators for old systems for that console.
as far as making back ups go, yeah you can do that. the easiest way is to purchase a Samsung SH-D162C dvd drive flashed with Kreon .81 then using either Xbox Backup Creator w/ imgburn or Schtrom360XtractV3.2 w/ img burn
if you don't want to spend the money on that drive, then you'll have to hot swap. here's a tut for that, i would seriously consider the samsung drive though, makes your life much easier.