OhYouBadKitten - pressing TAB (by itself) takes you from link to link. ALT +D takes you to the address box on Firefox, then TAB takes you to the Search box, and then to the first 'link' within the web page. Hope that clarifies.
For Caz10
On Opera and Firefox, CTRL + TAB jumps from tab to tab. When you mention Mozilla, I assume you mean Firefox (just that I have Mozilla v1.2.1 which pesters me to upgrade to Firefox and Thunderbird {mail).
Firefox normally shows the tabs in sequence (eg left to right) but Opera can be set to do that, or to show them in the order they were opened (I think that's the default). I use a mix as I do websites, and the latest versions (v9 on) of Opera allow me to keep bookmarks and other things synchronised (so every PC has the same bookmarks). There was an add-on for Firefox but I think it slowed FF down a bit too much, and disabled it.
Not sure how MS Internet Explorer handles tabs - I only use it to test websites when I feel I've finished them, and not in day-to-day use.
I've sometimes seen CTRL + TAB not working (also CTRL + F4 - to 'close' that tab) if Macromedia Flash is used, or sometimes when you are in some input box {like typing into MN} then some combinations might not work, so I click on some other part of the window and it then works.