They are listed by:
For example: apache_2.0.47-win32-x86-no_ssl.exe or apache_2.0.47-win32-x86-no_ssl.msi
Apache usually has installation packages in either .EXE or .MSI format. You can use either.... .MSI is Microsoft's package distribution format.
You can download either the EXE package or the Microsoft style MSI package.
.MSI is the secure Microsoft Format installation format, but some older systems or those with with somewhat corrupted registries may have problems with the MSI installer. If you click on the installation file and Windows doesn't know what to do with the file, Follow the instructions Here or just download the .EXE installation which is what my links try to give and save yourself some aggravation! Only one person reported a problem with .MSI, but just in case.....