Considerate N00B asking for some sound advice

Instead of fumbling through a process I've never undertaken and flooding you guys with a myriad of stupid questions, I thought I'd let you know what I've got and what I'd like to accomplish. If you could direct to threads/resources which are relevant, I'd appreciate it.

I have spent weeks scouring forums, wikis, torrent comments and random sites for the information I need and, the more that I read, the more conflicting advice and opinions I encounter.

I'm running an AMD set-up with Win7 Ultimate. If possible, I'd like to get a dual boot system running 10.6 without having to redo my windows install. Can it be done? If so, how?

Also, please could you point me in the right direction for a good distro? I don't need a link, but a file name and a decent site to search would be awesome.

Anyway, this is what my system looks like. Please advise on resources I'll need and any considerations I should take into account. Thanks.

OS:
MS Windows 7 Ultimate 64-bit
CPU:
AMD Phenom II X6 1090T
RAM:
6.0GB Dual-Channel DDR3 @ 668MHz (9-9-9-24)
Motherboard:
ASUSTeK Computer INC: M4A89GTD-PRO/USB3
Graphics:
NVIDIA GeForce GT 430
SyncMaster (1920x1080@60Hz)
Acer AL1717 (1280x1024@60Hz)
Hard Drives
977GB Seagate ST31000528AS ATA Device (SATA)
Optical Drives
Optiarc DVD RW AD-7260S ATA Device
Audio:
High Definition Audio Device