You may try this one: http://www.thegtaplace.com/downloads/file.php?id=3426 or search for some skin mods at GTAInside.com.
If you have any questions regarding installation, let me know.
EDIT: Ohh, I forgot... You told me that your son wants to put some Spiderman mods on his PS2 version of Vice City. Unfortunately, it isn't subjectively possible - it is possible to mod the PS2 version, however due to legal and technical reasons (such as the fact that you have to burn a new DVD every time you make a mod, and that you'll have to tamper your PS2's internals, which violates copyright laws in some jurisdictions), we won't tell you how to do that, much to your son's disappointment.
My best bet is to buy the PC version of the game instead; after all, you can get a copy for just 8-10 US dollars, either at your local software shop or online via Steam. It is much easier to modify the game's data files if you do it on the PC...