Solution to MAS - "One Moment Please... Connecting to iTunes Store... Loading"
This solution was found at one of Apple discussion board provided by user called "Crazy". This solution worked for me.
You basically have to delete three files. Here is the procedure.
1) Go to you home folder. (your user name under places on the left hand side)
2) click on Library
3) click on Preferences
4) delete "ByHost" which is a folder.
5) delete "com.apple.appstore.appstore.plist" which is a file.
6) delete "com.apple.storeagent.plist" which is also a file.
7) restart
8) empty trash
9) open Mac App Store and it should work.