Vehicle Installation
San Andreas Mod Installer v1.1
Includes Microsoft .NET Framework 1.1 as a separate installer since this is required on some versions of Windows.
Download (http://cy-fox.com/bcsd/SAMI.zip)
Skin Installation
IMGTool v2.0
No known dependencies. Highly recommended that you backup the GTA3.IMG file in your "GTA San Andreas\models" folder before making any changes.
Also after making changes to GTA3.IMG, remember to use the "Rebuild Archive" option before closing IMGTool down. Otherwise San Andreas/San Andreas Multiplayer will crash on load.
Download (http://cy-fox.com/bcsd/IMGTool.zip)
Also:
Alci's img editor:
It's the same as IMGTool but, I find it better imo.
Download (http://www.gta-worldmods.de/phpkit/start/include.php?path=content/download.php&contentid=1840)