I find the minute I upload an RSS feed that has decent content (I usually put the latest 10 posts/articles from my site) to about 100 RSS directories (I love the ones that you just paste a url and click submit).. I usually get deep crawled within a few days.
you have any urls for that?....wait a minute let me rephrase that?...do you know any of these...I tried some and some already seemed to know about my blog. http://www.masternewmedia.org/rss/top55/ Yes the ones where you can just paste in a url are easier but is it worth signing up to the others as well?
That site is probably the best one out there.. I try to submit to at least 40 of the 55 (some are topic specific) and i've always had good results. Remember to update your site daily with new content so that your RSS changes. Then go to http://www.pingomatic.com and tell them all you've updated so they can recrawl.