Direct Mail Campaign Question

I want to set up a direct mail campaign, I've never done this before.

Target Market:
- Local Businesses that need webdesign/SEO/other internet marketing services.

What I want is:
- Professional direct mail that will create lots of leads.

What is the best template for B2B direct mail? Should I just buy blank envelopes, stuff a cover letter in there, stamp it, and let it go?

Thanks for any help.

I recommend using postcards.
-List up to 3 benefits
-Have a Call To Action...ie

"Your Very Own Business Website!"
Hurry! 50% Off First 10 Replies
Go to PUT YOUR WEBSITE Here

Postcards are cheap. Go search in Downloads
for Gary Halbert and Ted Nicholas. Direct Mail Gods...IMHO...just a couple of them.

Make that Money!

PS
Don't forget, Search Button is our Bestest Friend.

Here's an old but good secret; if you're going to use a sales letter / envelope combination, get yourself a $6.00 rubber stamp that reads "confidential" and stamp it on the outside of your envelope below or next to the postal address. It increases your open rate 2-3X one without.

I only have $50 right now. Designing and printing postcards cost a lot more than that I think.

I'm gonna have to go with the envelope and a sales letter, with color illustrations on web design, and SEO.

the "confidential" stamp is a good idea. think i'll use that