Carnation Software (http://www.carnationsoftware.com) says its MacWise terminal emulation for Mac is now available in the Mac App Store.
MacWise allows a Macintosh to be used as a terminal, connected to a host computer directly, by modem, local area network or over the Internet with telnet or ssh secure shell. You can connect to the host via serial, modem, telnet, ssh, via the Internet or local connection. The App Store version requires Mac OS X 10.6.6 or later and costs US$94.99.
MacWise emulates ADDS Viewpoint, Wyse 50, Wyse 60, Wyse 370, Televideo TV 925, DEC VT100, VT220 and Prism terminals. Supports ANSI and SCO ANSI color. Esprit III color is also supported in Wyse 370 mode. AppleScript is also supported.