Is it possible to have more than one version of XCode installed at the same time?
If so, please post any tip, tricks, or potential issues to watch out for.
EDIT:
The reason I want to install multiple versions is to try out the new sdk beta, but if the new XCode is buggy I want to be able to use the older version for my existing projects.
Yes, you can install multiple versions of Xcode. They will install into separate directories. I've found that the best practice is to install the version that came with your Mac first, and then install downloaded versions, but it probably doesn't make a big difference. See this Apple Developer Connection page for lots of details.
It's easy to have multiple XCode installs.
In the installer there's a pulldown for the location... you just need to pick a new location when you're installing the beta version.
These instructions from an Apple dev tools evangelist have the full details (Apple dev username/password required): https://devforums.apple.com/message/40847#40847
Then grab yourself a custom icon for the Beta version of XCode you're using, so you can tell them apart in the dock: http://iphonedevelopment.blogspot.com/2009/03/multiple-developer-tool-installs.html