Hi KevKraft,
Besides Kirk's tutorials on playing in dropped D which I just ordered and looking forward very much to trying, there is a very good DVD on playing in regular tuning by Warren Haynes of Gov't Mule. He has a great and very clean approach to
slide in regular tuning on the second part of his DVD called "Warren Haynes, Blues and Slide Guitar"
From it you can get to see the notes he plays and start to get a road map of the fretboard from a slide perspective. The way I see regular tuning is that it is actually half open tuning (d,g and b strings makes open 'g' right?) so this can help a great deal. My only criticism of it the DVD is that Warren Haynes does not really explain clearly his right hand technique which is vital for muting unwanted strings etc.
Anyway, this is my first post here and I look forward a lot to learning from you guys a little more about the very underrated and still relatively unexplored world of electric slide guitar.
Best
Bearz