Sender ID Framework SPF Record Wizard
"This four-step wizard will guide you through the process of creating a new SPF record for your DNS domain. You should add this DNS record to your domain's DNS configuration. Note that you may need to manually edit the SPF record created by this wizard if you want to use some of the more advance features of the SPF format. For complete details please refer to the SPF record specification at http://www.microsoft.com/senderid."
I discovered this while reading Gerod Serafin's blog.
[UPDATE]
Uuups... I forgot to mention that the wizard is available here.
Meanwhile I found out that there is another wizard at this site.