These are sites that I have found useful:

A link to hiking in the Phoenix area. A first time visitor to the state found it to be very helpful and suggested that I should add it to my list. Included are tips for traveling in the desert.

A mineral and locality database. I use this site to find basic info on mine sites that I might be interested in visiting. Listings provide lat/long co-ordinates.

A USGS site that I use to download topo maps especially those outside Arizona.

A site that specializes in listings of places to hike in Arizona

An Arizona game and fish department site that reports lake levels and river flows for the larger lakes and rivers of the state.

A site with comprehensive listings for streamflows in Arizona

Discussion forum that includes history and current status of ghost towns and old mines

Discussion forums that specialize in the areas around Death Valley. That part of the country is extremely rich in old mining locations!

This is a site for kayakers and canoers. I look in on the message boards particularly the one that answers questions and dispenses advice

A virtual jeep club forum that specializes in Arizona.

A Toyota(mainly land cruisers) that focuses on Arizona

Really well-developed websites by folks who have been to a lot of old historical sites around the Southwest. They rarely give-out the real names of the places that they describe. You really have to be a detective
to get useful information from these sites!

A four-wheeling, hiking, biking website that includes detailed descriptions of Arizna trips with gps co-ordinates

A site dedicated to outdoor exploring with an emphasis on exploring ghosttowns. There is a forum, blog and directory. Contributors seem to be mainly from Nevada and California but other states are represented

This website provides information on the history of firebricks.

I use this site to look up the lat/long co-ordinates for named features on topographic maps

I really find stamp mills to be interesting. This site describes the various kinds and identifies the parts and functions of those mills.

When it rains in Tucson, this site reports rainfall totals from remote rain gauges spread around the town and the surrounding area.