buckworks - 3:28 am on Aug 25, 2002 (gmt 0)
If you think the site is well done and has a savvy webmaster, I say, go for it. A well-worded link from a site of similar theme can reinforce your target keyword(s) even before it has built much page rank. If you're one of the first people they trade links with, they might well be more accommodating than usual for making sure your link back is worded exactly the way you want, and as the other site develops its web presence the link will grow in PR value too. Think of this link exchange as an investment in the future, not just "doing a favor". And not so very far into the future at that!