The best advice I can give, it be KSHSAA certified... sure the $40 fee is steep but you make that back working either subs or districts or both, easily.
I started and was full of questions myself. First find out when the KSHSAA rules meeting in your area is (it'll be this coming fall) and attend that meeting. There will be all sorts of coaches/officials there so you'll know you're in the right spot. Either pay the $40 for the KSHSAA test packet or skip it, listen to the meeting, then afterwards there will be a Kansas Kid's Meeting, where you pay $5 and become a registered Kansas Kid's Official. It's the cheapest route but you aren't qualified to work any of the qualifying tournaments or State, but can work everything else.
About finding work, make up business cards and give them to coaches you know or other officials. The way I was able to fill my schedule this year was to wait until the tournament calendar for 2006-7 is published and then contact the person to contact for the tournament you wish to work, and usually they can tell you yes or no right there or can refer you to another tournament. You can also befriend other officials who can put in words of good advice for you wherever they go and can help get you in places.
Any other questions let me know, Alex