We liked Buying a Home: the missing manual. It's not new, but it has a lot of solid information.
Start seriously exploring specific areas way ahead of time. Go to open houses and community meetings in areas you're considering. Take walks, visit local library branches, festivals, restaurants, parks, stores, cafes--whatever. I found it well worth some pricey cappuccinos (which I love :) to spend a few hours checking out different areas of the city. I asked fellow cafe patrons if they lived in the area, what it was like, etc. Check out crime stats, of course, and local property tax rates.
If 20k is almost 20%, you might be in an area where it makes more sense (financially at least) to buy a house that has already been fixed up. That's the kind of area/city I'm in. Don't underestimate the time/opportunity cost of fixing stuff. Of course, if you want to fix, that's different.
I wouldn't buy without 20% down, but I can see that it might make sense in a few cases.
Get a good realtor who respects your priorities, and consider using a loan broker (as well as shopping rates on your own). Our broker made things much easier than the process tends to be, from what I hear.
Good luck!