Captcha within Form

I was thinking about doing this with an include() inside the weblinks module, but I'm wondering if anyone knows of a better way to go about this; possibly using captcha.module instead.

In the weblinks module, there is a form printed to the screen that allows the user to add a weblink. I need to add a captcha image to the bottom of the form above the submit button - I've tried using the captcha.module, but it appears only to apply to registering new users or submitting comments. How would I add it to all of my web-based forms, any ideas?

Thanks!