In Windows XP or Vista, you can do this by following these steps:

1) Create a desktop shortcut to Firefox

2) Right-click and choose properties

3) Use a mouse click or the “Tab” key to focus on the “Shortcut key” form field

4) Press whichever keyboard key you with to use. (I chose “F” - which automatically populates the field with “Ctrl + Alt + F”

5) Click “OK”

6) User your new keyboard shortcut to open Firefox

7) Select the “Tools” menu, then “Options”

8) On the “Main” tab, set the pages you wish to open in tabs each separated with the vertical bar symbol “|”

e.g. http://news.bbc.co.uk | http://www.google.com | http://www.beatnic.co.uk

The above will open BBC News, Google and this website each time your start Firefox.

Enjoy :-)