PortaServer is great application for blackberry where you can use your blackberry devices as web server, and other device can access is via wifi of blackberry. You can view or download pictures, music, videos, documents or web pages directly from your handset over a WiFi connection. The web server provides a password to protect your data from random visitors; this password is displayed on the main screen of PortaServer.

This application almost same with HTC wifi router, just check out that posting. Portaserver is freeware to download