http://www.adobe.com - the official web site of Adobe corporation, which created such famous programs, as Adobe Premiere, Adobe Acrobat, Adobe Photoshop. On the web site you can download demos of all software, upgrades ad buy them on-line.

http://www.microsoft.com - Heh. I hope you know what a company it is... Here you can download Windows Service packs as well as updates for some Microsoft software.

http://www.macromedia.com - do you know what is Macromedia Flash or Macromedia Fireworks? On this site you can buy them on-line, download demos or just read about them and many other products and their possibilities.