Sounds like you need to re-visit the tool(s) you're already using - the "free SEO tools" you find in the wild are hardly as accurate or useful as information made available by Google. (Though there is a certain amount of amusement in visiting the #2 search result for "best SEO tool")
I want to find out keywords that a
site is optimized for by typing in a
Go to the Adwords Keyword Tool and, in the Website field, enter the URL.
I want to find out competition (a
number) for a given phrase or keyword
- Google Jeyword tool gives a visual bar. I need a number so I can sort the
data in Excel
Try "estimated CPC" (which reflects the economic competition - why bother optimizing for key phrases which aren't worth money?) ...
... or use the Download > CSV for Excel option and presto, that graphical column is converted into a numeric value.
When it does come time to pick your
keywords, you'll want to pick the
keywords which are most specific to
what your site is about (there's no
sense trying to optimize for the word
"food" if your site is about "canned
lutefisk", for example) and, amongst
the terms which match what you offer,
you'll want to pick the terms which
get the most traffic (and, if you're
selling something, the terms which
result in the most purchases).
Per Virtuosi Media's comments, this proviso was lacking.