In Word 2007, you have "Developer Tools" for this. I'm not sure if this feature was available for Word 2000. You might search your help section for functions like "Text Form Fields," drop down menus, or forms.

In the end, a Word file probably isn't the best tool for sending across the internet. A better approach is to make your form in Word and finish it in Acrobat Professional - using Acrobat's form features. Then people who don't have a compatible version of Word on their system can still complete and return your form.