Pick a different business to get into if you have any brains. Loan origination is the most regulated business in this country and it's only getting worse with new rules in 2014 that affect compensation and credit quality that makes you criminally liable for violating. Launder money for drug cartels and terrorists, no problem! Have a loan default 5 years down the road and you had nothing to do with the credit decision, go to jail! This business is getting more difficult, the amount of business is shrinking and the big banks are just buying business by offering port products way below conventional terms. Unless you have a set network of referral sources I would expect you to lose money, possibly a lot, before you start seeing any traction. Do yourself a favor and find another business, if I could go back 13 years and make another choice even with all the money I've made I would not choose to do this with the way things are now.
Credit Services - There are a bunch and they all charge about the same, Informative Research, Credco, etc.
AUS - VA takes Fannie Mae's DU, this ties into your LOS as you run DU through that. You need Fannie Mae credentials
LOS - Most popular and easiest to use system for brokers is Encompass, would highly recommend it.