Mac OS X: Change your User ID
Recently I connected my Mac to my linux based NFS server at home. I use NFS to access files from two other Linux boxes and on each server my UID (unique id) is set to 1000. In order for me to easily have full access to my NFS shares from OS X I changed my UID to match:
dscl . -change /Users/will UniqueID 501 1000
chown -R 1000 /Users/will
Remember to run the chown command afterwards, or you will not be able to access your home directory. Finally, log out and log in.