Yes. Analog telephones can be used with Press 8's hosted PBX services.
An Analog Telephone Adapter (ATA) is required, such as the Linksys PAP2T. This enables your analog telephone to be used on IP networks.
For information on this hardware, please visit the following URL: http://www.press8.com/accessories/215-voip-adapter/.
Keep in mind though that if you use an analog phone you are going to be missing some highly utilized features that you could use on a VoIP phone like transfer, conference, and DND.
It is recommended that you use VoIP phones with any VoIP hosted PBX system such as ours.