Add some help text

First off, good work on the module. I'd been meaning to setup a sitemap for my site for a while and now I've got no excuse. These are really just polish items:
*Could you add some help text to the admin/settings/gsitemap page. What exactly do the the node adjustments affect do? How do they affect google's indexing frequency? Maybe a link to Google's help?
* Make the generated sitemap URL more obvious. I couldn't figure out what URL to submit to Google until I accidentally flipped past the admin/modules page. Adding something simple like t('Your sitemap can be found %sitemap, array('%sitemap' => url('gsitemap', NULL, NULL, TRUE))); to the top of the settings page would be great.