You can use MYSMTP.eu with almost all email programmes, which provide the option of using ”authenticate” an outgoing SMTP server with a user name and password.
For now we have online manuals that make your setup easy and ready for:

• Outlook 2007
• Outlook 2003
• Outlook Express
• Windows Pocket PC 5.0
• Windows Mobile 4.0 > 6.5
• MAC Mail
• Iphone
• Thunderbird
• Entourage

The list is constantly updated. Go on to the setup manuals here