Today I have installed Liferay IDE in Eclipse Indigo using my Ubuntu 12.04 desktop. Here are the steps that I use.

  1. Install Eclipse Indigo(extract using archive manager). You can Download Eclipse IDE for Java EE Developers here: http://www.eclipse.org/downloads/packages/eclipse-ide-java-ee-developers/indigosr1
  2. Run the Eclipse Executable file 
  3. On Eclipse IDE go to Help and click Install New Software.
  4. On the Available Software Screen click Add… button.
  5. On the Add Repository screen type the following data for Name and Location field:
    Name: Liferay IDE
    Location: http://releases.liferay.com/tools/ide/eclipse/indigo/stable/
  6. Click Ok.
  7. The Added repository will now be in added in combo selection box. And Liferay IDE will now be added in the Table. Select Liferay IDE and click Next.
  8. Click Next.                     
  9. Accept the terms and license agreement and Click Finish.
  10. Plugins will now be downloaded and installed.
  11. After plugins download and install, accept that the content is unsigned by clicking OK.
  12. Restart eclipse.
  13. After you restart, go to Help then click About Eclipse and the Liferay Icon badge will be shown.

I hope that helps. 🙂
Credits to: http://www.liferay.com/community/wiki/