How can I switch to Apple's MobileMe? The only information given, is that I should inform my registrar that "web.me.com" should be used as a CNAME for my domain. Does that mean that I have to change the DNS to web.me.com?

Hello,

What Apple is referring to is a CNAME entry in your domain's DNS zone file. For example:

www 28800 IN CNAME web.me.com.

It is not a DNS change, but rather the addition of a CNAME record. You can see how to go about making changes to your done file on the following page of this wiki:

http://wiki.gandi.net/en/domains/management/gandi-dns-zonefile

After adding the www CNAME Record (web.me.com) in your zone file, *forward* sitename.com to www.sitename.com.