| | Re: I downloaded an app, then deleted it and now..
Wipe = Security wipe, whereby you restore the BB to factory settings, undoing any changes you made.
OS = Operating System. It's the software that runs your BB.
OTA = Over the Air. I don't recommend you load any OS via this method.
As tsac mentioned, spend some time reading the FAQ to help familiarize yourself with your BB. BlackBerry.com has a lot of information, as well.
"The price of liberty is eternal vigilance." -Thomas Jefferson