Onemail:
http://www.pocketpcportal.com/Onemail.htm
Is pretty good, although if youre interested in buying one of them
(Onemail or Pocket Hotmail) I'd go with Pocket Hotmail, its much cheaper. I haven't gotten sending to work yet, but I haven't really tried to get it to work either ;), I prefer to type them at my PC anyway, but I don't mind reading them on the go.
You might want to try this if youre still having trouble with Pocket Hotmail.