go to options then advanced options then applications, and then let the list load, and highlight the one you want to delete, and then press the menu button and go to delete and select yes, some apps require you to restart the device, but do that on the last one so your not restarting each time!
any questions use the pin above, ill be glad to help!
You can also delete using the Desktop manager program. There's a section called Application Loader and the brings up a wizard for you to add/delete apps when your BB is tethered to your PC.