While searching for documentation explaining the difference between "git pull" versus "git fetch", I found a nice blog posting covering this issue titled, git: fetch and merge, don’t pull.

The short answer is use 'git fetch origin' followed by a 'git merge origin/master'.  You can insert a 'git diff master origin/master' between the first and second command to see what will be brought in.

--Chris

 Online Git Book, "Pro Git"