With directory submissions you wont have much bother getting a pr1 and if you are using other methods then pr2 is certainly acheivable. Its refreshing to see a realistic expectation, instead of the usual "tell me how to get pr6 by next update"
I have once submitter , using submitter to 1000+ seo friendly sites but just approved about 100+, you can visit this website: www(dot)addurl.nu, better than using tools.
I would focus more on directories related to your niche in some way or other. If you get a ton of useless backlinks, it's not going to do you any good no matter how many you have.
I used a similiar service to submit my site to 1,000 directories but it's too early to tell how much of an impact it'll make.
1000 SEO Friendly Directories Submission will improve your websites Backlinks, PR & SERPS. This process goes slow in approval. Trying many things as Directory submission, Article Submission, blog commenting, Social bookmarking, etc. etc. Gives your site more visibility in search engines.