Seafoam? Do you mean the seagreen mutation? VERY pretty :)
In addition to birdbreeders.com, you can try hoobly.com, kijiji.com and upatsix.com. You might also want to check out the ALBS website; there aren't any current classified listings but they do have a breeder listing:
Links African Love Bird Society
There are quite a few lovebird lists on Yahoo. One of the most active is the LB_List:
LB_List : Lovebird List There are a lot of helpful people there...
If you're looking for particular colors, you might want to see if there are any ALBS-sanctioned bird shows in or around your area.
Best of luck!