firefox add-ons

[yogisworld]

I am a newbie to firefox.can anyone tell me how to install addons to firefox.i have a compressed folder which has files with extension .XPI.where these files are to be extracted ?.also please post all useful add-ons and tips for firefox.

[ThinkFree]

Extract these files anywhere.Go to TOOLS>Addons in firefox. Now drag the xpi files in the box that opened in the last step to install them.
One thread about firefox addons is there in the forum. Search it to know about useful addons.

[yogisworld]

thanks THINKFREE
few more queries
1)how to open HMTL file previously saved using IE?
2)how to use older versions of adons in firefox 3.1 beta?
3)how to confirm compatibility wih newer versions before downloading addons?

[Ecko]

1)drag & drop
2)Use extension called MrToolkit or search forums
3)they automatically do