For a class at school I need a mac atleast version 10.5.7 to install the iPhone SDK on it. I have five computers I could possibly install this on, but, as this is my first attempt at creating a hackintosh, actually, it is my first journey out of windows... Any help you guys could give would be appreciated, thanks.

Computer 1: Dell Optiplex 745 (small form factor)
I have installed iATKOS V5i on it before, but, when I tried updating to iATKOS V7, OSX would no longer boot.
Processor: Pentium® D
Ram: 2GB 800 MHz DDR2 SDRAM
Motherboard: Intel® Q965 Express Chipset
Video: Intel® Graphics Media Accelerator 3000 or PCI Express x16 graphics card
Power Supply: 275 W
-> Link to Dell Documentation

Computer 2: Dell Optiplex 740 (desktop)
Have not tried this pc yet
Processor: AMD Athlon 64 X2 Dual Core Processor 4400+
Ram: 2GB
Motherboard: Unknown as of right now, something dell, likely similar to computer 1
Video: 128 MB ATI Radeon X1300
-> Link to DxDiag on Google Docs

Those first two are not my computers so I do not know much about them. The last three (my personal computers) I will post later tonight. Thanks for any help you guys can give.