Here's a funny fact. Search engines don't like searching deeply through
your site. Ideally every page on your site should be accessible within
2-3 clicks from you home page. This is also true for the visitors
visiting your site.
If you have a page that's only accessible by clicking through 5 other
pages, you're site isn't optimized and you should create links on other
pages to prevent this.
One way to do this also helps you out by making your site easier to
crawl. By creating text links on the bottom of your site you can
increase a search engines ability to jump around your site. You will
also increase your rankings if the text includes some of your keywords.
Many of you use images for buttons to navigate your website, but images
are bad for SEO (Search Engine Optimization) so you need to make up for
it.
Often times these links will mirror the buttons you have at the top of
the site, that's ok. You should also add other links as well that will
help to connect your site better.
Here's a tool that shows you a graphical map of your site, it's pretty
cool. Doesn't directly help you as it shows more than just links, but
it shows those as well. Check it out: http://www.aharef.info/static/htmlgraph/ and type in your website address.