Bootcamp on an external HD


Is it possible to run bootcamp on an external HD? I have VMware but have problems running PC games on it. I have windows 7 OS but it won't work.
It might work if you have an ESATA connection to the hard drive. This way the Windows 7 disk still thinks it is an internal disk. You can blame Microsoft for that.
Macbook pro doesn't have it. So, for setting up bootcamp; is it better to run bootcamp assistant or take it to the mac store? My only argument for taking it in is that I don't want to screw it up. Or is the bootcamp assistant that good? And if I only want to do it to play PC games how much should I set aside?
You can follow the clear steps in the Boot Camp install manual

The Boot Camp Assistant allows you to set whatever size you think you need for the Boot Camp partition. I think that 60 GB should cover most needs for Windows, especially one where you don't particularly need a lot of space for games.
If you are running 10.7, then Boot Camp is really optimized, and really only supports Win7.
If you want to use an older Windows, then you can find some help on that by googling for Windows XP Boot Camp on Lion
An article like this will likely help, if you need XP:
Yes you can install Bootcamp after you have installed windows to run on MAC

That makes almost no sense at all.
Bootcamp assistant comes installed on Macs since OS X 10.5
Its main purpose is to assist the user by creating a partition where you can install Windows.
If you already have Windows installed, then Bootcamp isn't really needed.