Compression

Abale Zip
Supports multithreaded Zip compression. By Abale.com. [Component, Commercial]
http://www.abale.com/

Chilkat Zip
Provides in-memory and file Zip compression. By Chilkat Software, Inc. [Control, Shareware]
http://chilkatsoft.com/ChilkatZip.asp

csASPZipFile
An ASP component to create zip files and control file downloads. [Comonent, Commercial]
http://www.chestysoft.com/zipfile/

Inner Media
Maker of DynaZIP and Active Delivery zip and unzip data compression component libraries. Active Server Page (ASP) compatible, with ActiveX, DLL, VCL, OCX, VBX and other interfaces.
http://www.innermedia.com/

Polar ZIP
Data compression component that supports multiple compression levels, and repairing corrupted ZIP files. By Polar. [Component, Commercial]
http://www.polarsoftware.com/products/zip/index.html

SA-Archive
Supports management of archives files (ZIP, CAB) including creation, extraction, enumeration and signing with Authenticode. Requires runtime licensing. By SoftArtisans, Inc. [Component, Commercial]
http://fileup.softartisans.com/default.aspx?PageID=124

Sax Zip Objects
Supports ZIP data compression. By Sax Software Corp. [Component / Control, Commercial]
http://www.sax.net/activex/compression/

Xceed Zip Compression Library
A software component that provides functions for compressing and uncompressing files and data. Its most popular functionality is the ability to create, read and write Zip files.
http://xceed.com/Zip_ActiveX_Intro.html