Can't open webpages after connecting to open wireless networks

I recently setup a security-enabled home wireless network with a D-Link wireless router, on my Dell Inspiron 600m.  Now, whenever I take my laptop elsewhere and try to connect to open networks, I can connect BUT I can't seem to get my browser to connect to any webpages.  I was able to do this before I installed my D-Link router.  My home wireless network works fine and getting online at home is no problem.

 

The browser goes for a bit 'detecting proxy settings' but never seems to open a webpage.  Anyone with ideas on what I can do to fix this?