Good things to know before hiring an editor

http://www.writersdigest.com/online-editor/10-things-your-freelance-editor-might-not-tell-you-but-should

A great perspective on the cost of editing

http://www.smallbluedog.com/why-are-book-editors-so-expensive.html

Query letters

http://www.agentquery.com/writer_hq.aspx