http://www.bad-neighborhood.com/text-link-tool.htm
Text links are an important factor in today's search engine optimization, and exchanging links with other websites is a good way to get them. However, doing a link exchange with a website that is penalized can have some detrimental results.
This tool will scan the links on your website, and on the pages that your website is linking to, and flag possible problem areas. This can greatly ease your seo efforts.
For an explanation of what the various visual cues mean, mouse over them for more information.
NOTE: Take the results with a grain of salt
More resources/trends/interesting tips here:
http://www.highrevenue.com