Fatal Errors-Cannot access admin.

I am new to WP, and I am trying to get a feel for it… unfortunately, I am not able to get to do much. I can see the default blog and navigate through it, but when I try to edit a post or click the Site admin. page link, I get an error message similar to the following:

Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to allocate 46080 bytes) in /home/www/edgewatermarineconstruction/blog/wp-admin/includes/file.php on line 299

Any suggestions? Thanks!