What to exchange links?

My vBulletin forum is small but growing forum in it's infantcy for professional DJs. I'd like to exchange links with a couple of related sites. It's would be a simple text link placed on the footer of your board and I'd do the same for you.

I'm looking to keep my link backs under 5, I've already reserved one for Loco's service, so that leaves 4 open.

Thanks,
Dan