I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
It would be helpful to know the specific phone and app, as well your intentions.
But in general, apps that are downloaded from the app market can usually be un-installed from the app's page in the Market. Also, most Android OS-equipped phones have some form of "applications" page in the settings and from there, app can be uninstalled, but I can't give you specifics for each phone.
If an app came pre-installed on your phone, then it can't be un-installed. This is usually apps like Skype, Blockbuster, City Lights, Madden's NFL, VZ Navigator, and maybe a few others, depending on the maker of the phone.
This is about all you can get from anyone without knowing more...