Calling helpers/classes inside another helper

[eluser]simonspoken[/eluser]
I'm writing a helper at the moment to do some custom session tracking, and I'd like to be able to access parts of the URI using the URI Class.

$this->uri->segment(n) won't work (throws an error about the use of $this) - what will?

EDIT: Turns out you can't use other classes inside helpers. I'll create a class instead. Cheers