This is strange. When my daughter got her iBook in December, she was happily mailing back and forth using her dotmac account and her own domain name. Then she allowed the dotmac account to lapse at the end of the free period. When I resubscribed her and went through the 'We want you back' screens, I'm certain the first field asked if she had another domain name she wanted to use. We put it in, but it doesn't seem to work for incoming.