Adding password creation to registration form (Civi + Wordpress)
Yes, assuming you're talking about a public-facing registration form and not the back-end form.


Go to Contributions menu » Manage Contributions.
Next to the listing for your membership page, select Configure menu » Include Profiles.
Note the name of one of the profiles you're including on the page.  If you don't have one, include one!  If you have two, either will do.
Go to Administer menu » Customize Data and Screens » Profiles. 
Find the name of your profile, and next to it click the "Settings" button.
Under "Advanced Settings", set "WordPress user account registration option?" to "Account Creation Required" and press "Save".


That's it!  To test it, make sure you're logged out.  You can't create a user if you're already logged in, since that means you have one!