search-function for commercial websites with google/yahoo

hello,

I need a search function for a commercial website containing only static
html, so I thought of the site-search function of google/yahoo.

Both offer this, but I'm not sure it's free for commercial use
(their conditions of use are quite contradictory in this respect...).
Can somebody please clarify this?

Also: I guess including the logo in the search-form is mandatory, right?

thanks!

--
Felix Natter