So I am new to this forum but not new to a blackberry.
I have used and installed 3 different BB spy software programs. I have researched what is one the market. Are only 2 that work on the BB model 8900 in true stealth mode. I will not post the names here (cell snoops is not one of them). If you wish to know more about the software can private message me and can send you a blog web page that has lots of information on cell phone spyware.
To get rid of the software if suspected on your BB then due a security wipe (like others have suggested). Do not need a 3rd party program to do this. Can Google your model to find out how. It is the only way to get rid of the software. Once wipe is done and rebooted can install backup file but not 3rd party software unless you know what it is.
HOW TO AVOID CELL SPY WARE - always password protect your phone. Cell spyware can only be put onto a phone by downloading it directly to the phone over internet/data connection. Someone needs access to your phone.