I have setup a links exchange on my website - I am a wedding photographer so only want to link to people who are in the wedding or social photography areas.
As I am sure you know google places GREAT weight on getting quality back links - these are links from sites within related fields such as other photography or other wedding sites.
The key to building good back link traffic is not to have a text link something like click here or www.davidpurslow.com - but its so much better to have a link saying something like - Worcestershire wedding photography - that way when people google worcestershire wedding photography your links come get you much higher up the list than just a www.davidpurslow.com link will.
I have set up a Links Exchange on my site, its linked off my main index.html page so google finds it easily - its not aimed at brides finding you but is aimed at building good quality highly valuable back link traffic.
If you would like to exchange links with me just go to http://www.davidpurslow.com/blog/link-exchange/
and follow the instruction on there
Good luck - lets all build our pr's to get higher on google
Oh when I started doing back links manually I was a PR1 site - in 3 months I have gone to a PR3 site ! - this stuff really works.