I came across the first trainers for GTA San Andreas PC in the morning today.They're nothing fancy, but they should help you through seeing we have no PC cheats at this point. Run these trainers alongside the game, Alt+Tab out and choose your options.

Download ReVOLVeR +4 Trainer (92KB/RAR) - Gives you "god mode," unlimited ammo, money and time..
Download ReeBSaW Money Trainer (96KB/RAR) - Gives you $10,000,000 instantly.