Treo Mail Internet Edition is aimed at customers using POP3 (Post Office Protocol 3) e-mail accounts accessible through the Internet, and Treo Mail Corporate Desktop Edition aimed at enterprise users who need to access their Microsoft Outlook, Exchange or POP3 e-mail from behind a firewall.
The e-mail programs round out the list of features offered by the combination PDA and mobile phone, which was launched earlier this year.
The Internet Edition costs $49.99 (£34) for a year subscription, while the Corporate Edition costs $99.99 (£68) a year. Users can sample both versions through a 30-day free trial by downloading the software from Handspring's Web site at www.handspring.com.
The e-mail service subscription fees are in addition to the extra airtime minutes mobile phone service providers may charge users.
Treo e-mail is powered by wireless service provider Visto, and is optimised for the Treo communicator, allowing users to program one-button e-mail access and select a range of delivery options.
The mail services are compatible with the Treo 180 and 180g, as well as the forthcoming colour Treo 270 communicator.