How to add the domain to your "safe" list:

Outlook 2003
- On the Tools menu, click Options. 
- On the Preferences tab, click Junk E-mail. 
- On the Safe Senders tab, click Add. 
- Add the domain. 
- Click OK. 

AOL
- Click the Mail menu and select Address Book. 
- Wait for the Address Book window to pop up, then click the Add button. 
- Wait for the Address Card for New Contact window to load. 
- Add the domain into the Other E-Mail field. 
- Make this the Primary E-Mail address by checking the associated check box. 
- Click the Save button. 

Hotmail 
- Open your mailbox and click Options (upper right corner). 
- Click the Junk E-Mail Protection link (top of page). 
- Select the Safe List link (second from bottom). 
- Add domain into the dialog box titled Type an address or domain. 
- Click the Add button next to the dialog box.

Mozilla Thunderbird 
- Click the Address Book button. 
- Make sure the Personal Address Book is highlighted. 
- Click the New Card button. This will launch a New Card window that has 3 tabs: Contact, Address & Other. 
- Under the Contact tab, add the domain into the E-mail dialog box. 
- Click OK.

Yahoo! 
- Open your mailbox and click on Mail Options (upper right hand corner). 
- Select Filters (bottom left corner). 
- Click the Add link on the Filters page. 
- Update the From header: rule with the following 2 pieces of information: contains and add the domain. 
- Click the Choose Folder pull-down menu and select inbox. 
- Pick the Add Filter button.

Gmail 
- Click Contacts along the left side of Gmail page. 
- Click Add Contact. 
- Add the domain into the primary e-mail address dialog box. 
- Click Save.