Built into the system there is no option to uninstall the files using an uninstaller so you can either make an uninstaller yourself or remove the files manually.
The best method to determine what files have been installed is to get a hold of the original .pkg if possible. If this is not possible you can also use the receipts instead found at /Library/Receipts. Your biggest issue is when you are dealing with a .mpkg which contains multiple .pkg files as you will then have to find all the seperate .pkg files in that folder (thankfully not that difficult when sorted by date).
Once you have the .pkg file (Receipt or the full install file) you can then use a utility to either create the uninstaller or find the files so you can remove them manually:
Uninstaller
LanRev InstallEase is a free program that can create uninstallers from existing .pkg files. Make the uninstaller .pkg file (note: You'll need Apple's Developer Tools installed to actually make the .pkg file)
Manually
Using a program such as Pacifist or a QuickLook plugin like Suspicious Package you can view what files are installed and at what location. Using that list you can then manually navigate to those folders and remove the files. I've used this method personally countless times before I discovered InstallEase, but this is still often faster if the install isn't spread out among many locations.