I know this post is VINTAGE! And reallllyyy old, but I would like to add something for anyone who reads this.
I know someone who had LawnBelt, and said it was great for half a year, until he started breaking pipe just by aerating his lawn and kids "playing" over it. Since its only 1" (if lucky) below the top, footsteps hit the pipe causing pressure over them too.
For the current price it costs with just basic spray heads, no safety vacuum breaker to prevent "crap" from flowing back into the water supply, and pipe thats gonna break in less than a year, you can get a pretty good (semi-proffesional) system for the same price, maybe a little less, and have it last for many years.
If you don't want to go through having a valve box, and timer/wiring, having to connect to a mainline and everything, you can do it easier.
Get regular 3/4" poly pipe, however much you need, and some fittings needed for the connections and poly clamps. Rolls are about $20 for 100ft at HD. Fittings about $0.50 a piece.
Hose bib vacuum breaker- $5
Sprinkler rotors. $10 each for some Orbit Voyager II. Still will outlast LawnBelt, although for heads I recommend Hunter PGP's.
Bury piping at least 6" deep to protect it from feet and tools. You can connect the poly pipe right up to the hosebib and vacuum breaker with a little "fitting play", to have a nice easy connection. Use a Y splitter so you can keep you garden hose. You can add more zones by adding a larger splitter (4 outlet?), and repeating the steps above. Even add a hose timer for automatic watering. Make sure you have a vacuum breaker on the hose bib though! This is for your own protection. This is really the only "dangerous" part of irrigation.
Pretty much, this will be a regular system without buried valve manifolds and having to access your mainline and everything. This just connects to the hose. At the end of the year, blow em' out, and ya good!
Still about the same $ as LB, and better quality.