Here's what worked for me:
On your Omnia, tap Start, Messaging, Setup E-mail.
enter your email address without the "hotmail" portion, e.g., example@.com. This way, it won't try to connect to Windows Live.
Tap Next.
Details you'll need to know to get it working:
POP server: pop3.live.com
POP SSL required? Yes
User name: Your Windows Live ID, e.g., example@hotmail.com
Password: The password you usually use to sign in to Hotmail or Windows Live.
SMTP server: smtp.live.com
Authentication required: Yes
TLS/SSL required: Yes