paying for backlinks
Paid links are definitely against google rules. However, there a certain sites that you can pay for in which you are not paying for the backlink, but instead for the review. The company has someone manually review your website to see if it is worthy or not to be placed into the directory.
Like Yahoo's directory, you pay 299.00 for someone to review the website you are entering into the directory, you pay for the review, not the backlink. Google encourages the yahoo directory and other high quality directories that have a strong review process. thanks.