Opera & Greasemonkey
I am not quite sure how many know the fact that Opera is quite a competition to Firefox.Several of the useful features in Firefox are also available in Opera.Well i cannot say which one is the best..i use both!
Greasemonkey is available as an extension for Firefox which allows users to run ’scripts’ to modify the pages that they see.Now this feature is present in Opera (no plugin needed).And even more interesting is the fact that several of the Greasemonkey are compatible with Opera.However there are scripts available for Opera seperately also.I just came across this wonderful site called User Java Scripts which has several scripts for Opera,consider this something similar to the Greasemonkey Script Repository.
My favourite script is the Rediff Shrinking Ad fix!…(i regularly visit Rediff).Incase you too use rediff and Opera here you go!
Another good collection of Opera scripts is available here
Check out the Tutorials section to muddle with some code 
