Free Alternatives

Here a small List:

Proprietary	Open Source	Kind
WinZip, WinRAR, WinAce	7zip (x86,x64)	Archiver
Windows	Linux	Operating System
Internet Explorer	Mozilla Firefox	Browser
ICQ, MSN(LIVE), AOL, Yahoo	Pidgin, Miranda	Messenger
Outlook Express	Mozilla Thunderbird	Mail Programm
Editor	Notepad++
Microsoft Office	OpenOffice	Office Programm