Link building is perhaps the most time consuming part of the SEO process. As the

web becomes more social link building is moving away from analysis and

replication of competing channels to creating ideas that will spread on social news

websites and blogs.

show scraper sites, and useful hub pages. You can limit the search depth to

show more of the hub pages and less scraper pages.

http://www.linkhounds.com/hub-finder

Free: Link Harvester – gives lots of details about unique linking domains,

.edu backlinks, and IP addresses of backlinks.

http://www.linkhounds.com/link-harvester/backlinks.php

Free:: Class C IP checker tool checks for duplicate class C IP addresses

from a list of domains. Links from sites which are on the same C block IP

address may not carry as much weight as sites from different C block IP

addresses.

http://www.ip-report.com/

Free: Back Link Analyzer – operates similar to Optilink and SEO Elite,

but is free. If you like BLA then you probably have no need for Optilink or

SEO Elite since the feature sets prettymuch overlap.

http://tools.seobook.com/backlink-analyzer/

$167: SEO Elite – similar to Optilink, but also checks reciprocal link

partners.

http://seoelite.com/

Free: PRWeb – free press releases. I often recommend purchasing one of

their premium services though.

http://www.prweb.com

Free: DNS Stuff has a variety of webmaster tools including WhoIs, etc.

http://www.dnsstuff.com/