ZIp files? Help needed...

Hi people, I´m looking for alternatives in using zip files. Our users should upload into our server zipped files and we need to unzip this files and process it. I have read there is a library that could be used like an extension, but I´ve tried to use it from NT and don´t seems like the extension was added and when I try to use the commands PHP says that don´t recognoice the commands. In the other hand somebody has told me that PHP must be recompiled for using this library. Our platform is Windows NT but in the future could be Solaris. Anybody could send me your experience?