Here are a couple of things that I've done and other folks are free to use.
Naturally, they are provided with no warranty of any sort. Indeed, they are likely full of bugs. If you find any, please do let me know so that I can fix them.
Most may be distributed under the terms of the Gnu General Public License, version 2.
Swallow
A GUI MUA. It has its own page.
A cache that sits on top of PyDNS. It may be distributed under the same terms as the Python programming language.
ping.py
Sends a ping to a remote host and waits for the reply. Works under Unix
(requires root authority) and (I'm told) under Windows NT (at least NT4).
Almost certainly won't work under 95/98/ME.