I decided to learn WML today (used for web browsing on cell phones and other small wireless devices), and METARs and TAFs seemed like a good, simple project. If you’re using a WAP-enabled device (i.e. your cell phone’s browser), try visiting this URL:
Type the ICAO identifier of an airport into the text field, and you should see a METAR and TAF for the airport, if available (not always the latest, unfortunately; I need to find a better source). This is more for fun than real flight planning, but feel free to play around. There are for-pay services that provide a lot more, including weather maps.