Yes you can edit  template used to create the "My Sites". If you do edit the
template however it will effect all of the "My Sites" currently created as well
as any that will be created. To edit the template, or what I do at least is to
open up the main site in frontpage 2003. Once you have done that click on the
folder named "My Site" that should open up that folder and yo will have two
files, default.aspx and public aspx, if you want to edit the public facing page
edit public.aspx and if you want to edit the personal page edit default.aspx.