i'm posting as i was unable to find much information online about how to replace an HTC incredible digitizer/glass screen!
to start: i don't consider this an end user-replaceable item. i suggest picking up insurance! if you've cracked your screen and it still works, put a screen guard or packing tape over the screen and keep using it. this repair is fairly annoying.
i picked up a replacement digitizer from a foreign seller on ebay, which cost about $70 and arrived without issue. it showed up with three tools: two torx screwdrivers of various sizes and what is essentially a miniature plastic crowbar. i additionally needed (i think) a #00 and #0000 philips head screwdrivers (to remove the circuit board and lcd, respectively), a small knife, an x-acto blade, tweezers, and double-sided tape.
up to the point where you need to remove the digitizer, the techrestore video ( ) is totally accurate (they do not show that there is a rubber gasket that in the photo button recess that rests between the main board and front housing; be careful not to lose this). they do not remove the digitizer. after watching a few iPhone digitizer replacement videos i was filled with relative confidence...
the digitizer is affixed to the front of the phone housing with gooey black foam adhesive along every surface where it comes in contact with the housing. before starting the repair, as my glass was quite broken, i covered the glass in packing tape. in order to remove it, i used the plastic crowbar as a wedge to work between the glass and casing around the edges of the casing until i'd loosened much of the adhesive on the sides, after which point i was able to get the top away and very, very slowly pull the glass away from the bottom of the casing. if you do this quickly, or apply too much force, you will break the digitizer glass. there is a contact strip of circuitry adhered to the inside of the front casing which sits behind the row of home buttons on the phone; i left this alone.
at this point i covered the broken insides of the digitizer with tape as well and set it aside. the broken glass at the top remained glued to the casing with the adhesive, and you can see in the following picture that i removed the glass shards and stuck them to some tape: http://www.monkey.org/~mlis/repair.jpg. fwiw, the cracks in the glass are all from the original damage, and were not caused by my repair attempts.
in the picture i have already scraped off about half of the adhesive, which comes off the plastic well but does not come off the metal inset well at all. :P i used the plastic tool to scrape away most of the adhesive and the tweezers to pull it away when convenient. the metal inset essentially surrounds the inside of the visible opening
after cleaning the entire casing so the surface that would mate to the digitizer was flush, i used an x-acto knife to cut double-sided sticky tape to sit inside the front casing; as the foam adhesive had some thickness to it i put in two layers of tape. i imagine you could also use a contact adhesive, but i would be quite careful about the flexible circuitry i mention above. the circuitry is also why i avoided using any sort of solvent on the adhesive.
after lining the case with tape, i set in the new glass and reassembled the phone. it works. this took about 4 hours. i am not terrifically optimistic about this phone's longevity...
this might be an easier repair if you acquired the housing + digitizer, while this probably means you'd have to move the flexible circuitry & speaker, and figure out how to stick the two pieces together, you will save yourself a few annoying hours dealing with goo and avoid dealing with broken glass.
if you have steady hands and don't consider soldering intimidating, it's a do-able repair, but keep in mind it's not trivial. good luck!