[eluser]BrianDHall[/eluser]
Absolutely. Check the index.php file for a link to 'system' and 'application' folders. Pull out your 'application' folder from system and rename it, say, application1 and put it anywhere you want. Then take your system folder and feel free to rename it - I name mine something like ci_1_7_2, and put that somewhere.
Then just update your index.php file with the paths/names to these folders, and you are done. You can easily share 1 system installation for a logically unlimited about of applications.