flashing new rom but need help

[Guest csellyn]

Ok, I know I am very late to the party and should be flogged for asking but I would like to flash an unlocked ATT SMT-5600. I have found two files (Cingular.bin and Cingular2003SEsmt5600.rom.img). I found many different methods here but do not want to turn my phone into a brick (nothing on you guys...just my bad luck. I know you guys have used many programs including WinHex and a few tools but a buddy of mine insists he only used a few key strokes with an img on the SD card.

So I humbly ask: What do I need to do?