I'm sure the old-timers out there are aware of this, but for the newbies out there I wanted to say...
Banner Exchanges do not work. We have tested nearly a hundred banner exchanges, and with almost all of them we have lost far more traffic than we gain.
This is because most banner exchanges only provide an exchange ratio of two for one, so for every two times you display their banner, they display yours (with a plug for their company under it) once. Look at our stats. for the LinkExchange, the best known banner-exchange on the net:
Banners displayed (on our webpages): 7,000
Our banners shown (on other sites): 3,500
We tested various professional-designed, animated banners!
Actually, the 55 hits we received is considerably better than most webmasters attain. The average click-thru rate of banner adverts has plummeted to less than 0.5% over the last four years - which is about 15 for 3,500 banners displayed. The simple fact is that surfers have become 'immune' to banner advertising and ignore them. We do not recommend you use most banner exchanges. They clutter up your webpages, the amateurish banners displayed on them make YOUR site look unprofessional, and bring you very little traffic in return.
Instead, a better thing to do is search for other websites targetting the same geographical location as yours or with a similar demographic breakdown. If they have a links section, write to them suggesting a text link exchange. You have nothing to lose and considerable traffic to gain :)