Inserting username into a form.

[Attilitus]

This is a really easy question, but for some reason I can't manage to do it.

I am attempting to create a link in each users postbit with their userid attached (url&userid="theiruserid") and have that information appear in a particular field on that page.

I am rather frustrated that nothing I have tried is working and would really appreciate a quick line or two detailing how to do it.

Edit:

I discovered how to do it. It turned out that my instinct to use the GET function was correct, I was just editing the wrong template the WHOLE time! It goes to show you the downfall of the "no sleeping" habits of coders.

[Wild-Wing]

$bbuserinfo['userid'] will do it

[Attilitus]

Although that is successful in posting the userid of the user who is browsing the site, it does not seem to post the username of the user with the userid in the url:
yoursite.com/something.php?do=something&userid=(the userid of the username that you want to appear in the form)