Here's some great resources for those interested in learning about slide guitar:

BRAD'S PAGE OF STEEL
http://www.well.com/user/wellvis/steel.html
"lap steel guitar is held in your lap facing toward you" You've probably checked out this great resource already... Search for steel guitar, and this page always comes up first in Search Engines!

SLIDE GUITAR 101
Seven Secrets for Beginners by Debra DeSalvo
"We’ll never know the identity of the first guitarist to take a bone or a polished stone and slide it along a guitar string. Since African slaves brought the technique with them to the United States, it may have originated in Africa. Then again, North Indian guitarists, like the amazing Debashis Battacharya, use slides, too..."
http://www.guitar.com/columns/viewcolumn.asp?columnID=58

HOW TO MAKE YOUR OWN BOTTLENECK SLIDE
You’ll need a few simple and easily found things to make your own slide:
* a ruler
* an empty bottle (wine bottles are usually best)
* a glass cutter (any hardware store will have one)
* a bowl of ice water
* a pot of boiling water...

Find out what to do with them:
http://www.guitar.com/columns/sidebar.asp?columnID=58&page=2

LEARN HEAPS MORE ABOUT SLIDE GUITAR HERE...

SLIDE & STEEL
http://www.GuitarSite.com/newsletters/990719/7.shtml
The slide guitar is typically a standard guitar, held the usual way, and fretted with a piece of metal or glass, typically a tube worn on one finger. The sound of the slide guitar can be quite similar to the steel guitar. Famous slide guitarists include Ry Cooder, Bonnie Raitt and Muddy Waters.

BONNIE RAITT
http://www.GuitarSite.com/bands5.htm#raitt
Bonnie picked up the guitar at age nine, and was on her way toward mastering a unique fold and country blues style derived from listening to recordings by Joan Baez, Bob Dylan, Muddy Waters, Mississippi Fred McDowell and John Hammond. Official site: http://www.bonnieraitt.com/

LEARNING SLIDE GUITAR
http://www.GuitarSite.com/database/Tuition/rec/565
Over ninety years ago , W.C. Handy wrote in his autobiography, Father Of The Blues, of being awakened in the Tutwiler, Mississippi, train station by the sound of a guitarist: "As he played, he pressed a knife on the strings of the guitar in a manner popularised by the Hawaiian guitarists who used steel bars. The effect was unforgettable. His song too, struck me instantly..."

SLIDE GUITAR AS A SECOND LANGUAGE
http://www.GuitarSite.com/database/Tuition/rec/1362
These free Slide Guitar lessons in RealAudio are taken from Phil Johnson's instruction video "Slide Guitar as a Second Language" this 2 hour video is the only instruction video that deals exclusively with slide guitar in standard guitar tuning. NO NEW TUNINGS to learn. Using Phil Johnson's innovative "behind-the-bar" fretting technique anyone can learn to play slide guitar in any style.

SLIDE GUITAR THE REAL BLUES
http://www.GuitarSite.com/database/Guitars/rec/584
Slide guitar tips, players, instruments, discussion, chat and outrageous blues opinions by Brian "King Bee" Robertson, author of Little Blues Book

TUNING SLIDE GUITAR
http://www.GuitarSite.com/newsletters/2.htm Open vs normal tuning slide guitar, by Kirk Lorange

This GNW article also reviews many of the best slide & steel sites & artists:
http://www.GuitarSite.com/newsletters/990719/7.shtml