Navigator from Purple Software allows the zipping and unzipping of files within its System replacement program.
http://www.purplesoft.com

RMRZIP from RMRSoftware is a excellent ZIP uiltiy for EPOC. It is best for Power users.
http://www.rmrsoft.com

Zip Manager from Epocware is another ZIP utility. It is probably best for those needing only simple unzip and zip functions.
http://www.epocware.com/zip.html

There is also a Java program called Zippy. It is freeware. However it is a little difficult to use, and being Java based can be slow and needs to EPOC JVM installed.