I noticed the following sites are usually pretty good with acceptance/rejection emails within a 1-3 day period:
(in no particular order)
jays-xxx-links
sexy-search
pornoplentyxxxlinks
link-fabulous
outlawsporn
freesitexxx (but not theporncollection)
fetishtown
sextoplist
free-porn-post
hqseek, sexyseeker and freepornoz
worldwebporn
sex-hot-sites
adult-xxx, clixxx4porn
pimplinks, thehornyguy
pun-an-i
bluewavelinks
surfnsfreeadultlinks
premium-sex-links
my-hot-spot
uglyworm
bizarre-sex-pics
explorexxx
hotslutlinks
adultporngateway
linkalotpuss
alienssexlinks, wildunicorns
fetishphiles
scorpiolinks
all-sex-links
awkwardamateurs
pornuwant, triplexsmut, webpornlinks
69freepornlinks
adult-bookmarks
4linx
pornhitz
There are several also that take more than a week, and in some cases much longer.
Also, there a large number of sites that don't bother sending emails and to be quite honest, they are so busy doing reviews and what not, I can't say I blame them really.
Thanks for the listings guys and gals!