CSS and User Registration

Try dropping this into your theme's stylesheet:

[css]
body .gform_wrapper ul li.gfield {
clear: none;
}

Have you setup a User Registration feed tied to this form yet?
http://www.gravityhelp.com/documentation/page/User_Registration_Add-On

Then that's how they get registered. When they fill out the form, the feed kicks in and creates the user upon submission.

This is honestly due to how your theme is set up (the columns and the floats). Try dropping this in:

[css]
body .gform_footer.top_label {
clear: none;
}