Hey Ed, welcome to the board, hope you enjoy your stay.
Mics huh, well depends on how much you want to spend. I hear (worked for me too) that starting out with a shotgun mic is a very nice place to start.
The Azden ECZ-990 for $60 is on the very low end.
Sennheiser MKE 300 for $160 kind of low middle price range.
Prices go up from there. Let me point you to B&H Photo/Video/Pro Audio web site to see for yourself.
http://www.bhphotovideo.com/
Plugging the mic into the camera might produce some unwanted sounds. Do some tests and see for yourself if you like it or not. A seperate audio system may be better.
Editing depends on if you're a Mac or a PC guy. I bought Vegas 6 and learned it very quickly, my friend has Avid and that program still baffles me. I've seen Adobe Premiere and it ranks up there with Avid.
Avid makes a light version too, not as expensive, I've never tried it so I don't know. On the low end of non-linear editors you can check out Ulead. They make a nice package called StudioPro $80 if you download it from their web site.
People who do editing, go to the Script to Screen section, sub forum Post-Production and ask away.
Good to have you here Ed. Stay fresh.