Instructions:
double click the sydney3.exe (Self-extracting WinRAR file).
Extract files to Quake2\<sub directory>\players\sydney

For example, if you're playing Action Quake2, extract the files to your quake2/action/players/sydney directory.  If you want to use these skins for Quake2 and other mods, then extract to quake2/baseq2/players/sydney (this will also work with AQ2, but you won't be able to see the skin in the player selection screen).

If you need standard VWep, AQ2 VWep, or soundpacks for the Sydney model, download them from NotriX (http://ntrx.cjb.net or http://start.at/notrix)