In an effort to make downloading author packages easier, the AMS has created .zip files for its author packages. This will allow you to download just one file containing the TeX files and instructions necessary to publish in the AMS publication you have selected.
Some typical examples of programs that expand .zip files are:
Many file compression software packages are freely available on the web - CNET.com is one place where these downloads are available. If you don't have a zip application, are unable to obtain one or have difficulties downloading this .zip file, you should download the individual AMS-LaTeX files located on the publication's Author Packages page.