CapiCall

ISDN-based voicemail and information software for 2 to 60 channels with touch-tone controlled menus.

The user can create own information menus quite easily.
CapiCall also allows voice to mail (creating e-mails with WAV attachments) and GSM SMS notifications when new voice mails are stored.
Based on the German version, an English Language Pack is available from:
http://www.shamrock.de/en/