Well as it's an ATMEL based device, you want the FLIP program. You can get that from here.
According to this page your product appears to be compatiable with the AT90USB1287 device... so just grab a PSGroove .HEX file from here (Hex File Collection For Various Boards) and that should be enough to get you started.
You may also want to search around the site for a compiled HEX to for whatever payload you want to use. I personally use Hermes v4b. Also, there are tutorials on how to use the FLIP programmer to program your device. I'm sorry, but all you're gonna get is "instruct" tutorials rather than full tear downs to teach. Why? Because people write them as simple as possible so we don't get n00bs asking the same questions over and over again... which they do anyways!
Honestly I suggest you just get yourself up and running, then look into learning how the FLIP program works properly later. At that point, you can also look into compiling your own HEX files.
60GB (120GB WD Scorpio Drive) PS3 (CECHA01, NTSC), 3.7OFW
60GB (640GB Samsung Drive) PS3 (CECHC04, PAL), Kmeaw 3.55, Repaired (Dead Laser)
PSP-1003 FAT, CFW5.00 M33-6 & Prometheus v2
X-Box 360 Xenon (JTAG'ed, 500GB HDD)