Check out this thread:
http://www.lawnsite.com/showthread.p...threadid=21313
There are links in there to a few companies that sell them. Even if you don't want to buy them, you can look at samples online or ask for sample products and get some ideas from there.
If you still need help, tell us specifically what service your trying to market and we can help you out a little bit better on this.
Hope this helps!