Question
Can you tell me anything about how to graft trees?  I am interested in grafting a Barlett pear to a Bradford pear also, pecans, hickory and so on.  Thanks

Answer
Here are a couple of web sites that will discribe how to graft a tree. The first is a how to book from Extension the other link is an ad for books on grafting. I would also check with your local State Extension office and see if they have some printed information on gratfing.
http://www.extension.umn.edu/distribution/horticulture/DG0532.html
http://www.geocities.com/RainForest/Jungle/6700/plants/propagate01.html