Well there is the HeaderText="" but this does not replace it it Just adds another Line above it.
If you want to completely remove or rename it I suggest
click on the control until the arrow at the upper right corner appears, then click on the arrow.
click on CustomizeUserStep
then it will display all of the controls in a table
the second <tr> is the label "Sign up for your New Account"
you may change it here and add style if you want -
Customizing does not change anything else with the control, it just lets you see all of the controls, in case you do want to change anything.
If you do not like the create user wizard and want to make your own custom form - I have a posting with code that shows how to make a custom create user using the aspnet_membership and making your own form.
http://forums.asp.net/t/1375441.aspx
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