when i log in, after a successsful log in i would like to be taken back to the page i was browsing, rather than the index page.

Awww mate! you read my mind!!

i think a variable contained in the "login" link will work just fine. Nice and easy.

it just needs to pass the current url over as a get variable, then use the php header(Location) to send you back to the page

[see my other suggestion about redirects]

edit: past tense converted to future tense