Airnav.com is a great web site for finding out about airports all over the U.S. It gives all the airport information, current weather, TAFs, Notams and Instrument procedures. It also gives current fuel prices with a page to compare other airport fuel prices. Here's a link to Crossville, TN (KCSV).

Uswx.com is a great weather web site for overall weather conditions featuring easy navigation to state and city forecasts.

Wunderground.com is a great weather web site that also has some useful aviation related information.

 Faa.gov - The Federal Aviation Administration's glorious web site. Caution! Hard to navigate!

Hi. We're from the FAA and we're here to help.

Hi. We're from the FAA and we're not happy till you're not happy.

Aopa.org - The Aircraft Owners and Pilots Association web site. Great information for all types of flying. 

 Flightaware.com - A great web site for tracking commercial and General Aviation IFR flights all over the country. You can follow flights by aircraft number, or you can follow all flights at specific airports. Lots of fun!

 Navmonster.com - A nice web site for GA flight planning. You can also find information about airports and other useful information.

This isn't airplane related, but it's kind of funny.

http://www.erieairpark.com/EngineersView.jpg