There is a great social submission tool for blogs, it's called autosocialposter. I use it, it's great. Also, you can try web2submitter, it's cheaper, but just as good.

I would suggest you go to PD forum. In the Buy-Sell-Trade forum Services section there are tons of people offer social bookmarking services.
DO NOT use ones that offer 100+ submissions.

You'll be better off using 5 different guys (girls) who will bookmark your site on 20-30 sites.
Make sure to give every one of them slightly different descriptions so this does not look like artificial duplicate submissions.

Try to do may be 1-2 submission a week so again it looks more natural.

After all 5-6 submissions are done you may want to buy some diggs and stumbles on the same DP forum.

I promise you - there will be a nice increase in traffic and at the same time you will get large increase in backlinks and SERP results. At least that how it worked for me...

All this project may cost you around $50 but it well worth it.

I would say this will be much more beneficial than submitting to 1000 free useless directories.

Give it a try and post some results after a month or so...

I think this is an excellent suggestion SkinnerW, I have never tried it but I will give it a go and see if it works as you suggested

I have a football predictions blog which I only stumbled and digg it, nothing else, no other form of advertising! I stumble and Digg every new post and this brings me around 500 uniques every week. Great source of traffic!

Directories are not useless, I had 150 backlinks from directories in 1 month.

Originally Posted by JeremiaSK8

Directories are not useless, I had 150 backlinks from directories in 1 month.

Congratulations... How much traffic you got from these 150 links?

Most of the people who offers a lot of bookmarks (I saw people offering 3000) in a short ammount of time, are scamming you. Why, because they have multiple accounts and bookmark your site from different accounts, and you get a lot less traffic than a few bookmarks from strong people.