[Guide]-Install Mac OS X Leopard OSx86 on PC Dual Boot Windows 7, Vista in Easy Steps
This currently works on INTEL system with SSE3 support ONLY. An AMD/SSE2 patch should come shortly. Use CPU-Z to check the system capability if you are not sure.
Update: AMD/Intel SSE2 users try this. Need to patch the original Leopard DMG though, no pre-patched disk available atm.
Most Important thing you should check for is your Hardware compatibility List (HCL) -- Hardware Compatibility List (HCL) - OSx86 | BLOG OUT LOUD!.
How To - Install Mac OS X Leopard OSx86 on PC Dual Boot Windows 7, Vista in 9 Easy Steps | BLOG OUT LOUD!