This map, called Vercetti Island has been created by us.
This release (v1.0) Will be updated with car spawn's, pedestrian spawn's and weapon spawn's in the future!

Installation instructions:

1. Extract the folder called "maps" with winrar
2. Go to C:\Program Files (x86)\Rockstar games\grand Theft Auto Vice City\Data\maps on windows 7 or
C:\Program Files\Rockstar games\grand Theft Auto Vice City\Data\maps on windows vista and lower.
3. now just copy the 10 folder's inside the "maps" folder you just extraced to the "maps" folder from vice city, and it will ask you
if you want to overwrite the files. click yes.
4. Load up GTA VC and go to Starfish island, you'll see a bridge leading to the map =)

Screenshots included in the "screenshot" folder 

video: http://www.youtube.com/watch?v=wbl2hZq8eVM