I dont beleive these sites / links have any use whatsoever , they will show up on google ( sometimes ) but dont think they do too much for your overall "rank credit" , take linkmarket as an example , we had tons of links on there but didnt really do us any good.
You can add your site to PR0 directory, but not to much help for your new site - just try improve your website first.
If google does not count PR0, the link has value in Yahoo and MSN, which also send good traffic. Overall i can say content is more important and few quality backlinks with any PR can get keyword rankings.
It's important to remember that just because the directory's PR is 0 now, it could be much higher in the future. Probably easier to get yoru link in now before it goes up.