www.xbox-scene.com is where you need to go.
Its quite easy to do, only takes 10 minutes but if you use the two wire trick dont mess it up or you will kill your 360
go on www.xbox-entertainment.co.uk mate. They do it you for 55 quid which includes picking the console up from your house and delivering it back to you a couple of days later. Brilliant once you've got it done best 55 quid i've spent on it, had about 5 mates have it done through that site as well all sweet
yeah u need to burn onto dual layer discs mate. Verbatims are the best brand to use for the 360 games but they're quite expensive. worth it though. Its quite complicated modding the firmware yourself, you need the connectivity kit first to connect the 360 drive up to your pc, a lot of hassle really