Check out the new adwords keyword tool http://adwords.blogspot.com/2008/11/announcing-search-based-keyword-tool.html ...this looks like it could help advertisers get better quality score.
After very quick play, first impression is that it will prove most useful for generating keywords when setting up new campaigns but also a useful check for those with existing campaigns to make sure nothing has "slipped through the net". Just appears to be one major error in the Ad-share/Search-share results. The information that pops up for "about this data" says, while the tool-tip says, Given the numbers that are showing up it would suggest the tool-tip is the correct information, i.e. Ad-share = frequency that one of your ads (already) appears on page 1 for the suggested search term/keyword, Search-share = frequency that your website appears on page 1 in SERPs (natural or organic results). But, no, it will not help your QS, that will still rely on relevance and writing relevant ad text, etc. I suppose it depends how diligent you are with keyword research but, if you know your way around Adwords, this tool is not going to tell you anything you do (should?) not already know.