There is a Firefox add-on with bioinformatic tools:
bioFOX Installation will give you access to a lateral panel menu. As you see, you will be able to make some nucleic acids manipulations, protein statistics or molecular weight calculation. You also have shortcuts to few servers as Blast, Pfam...
In my opinion, it is an interesting add-on if you don't like to waste your time searching for online bioinformatics tools. It's also easy to install, but there is only basic bioinformatics tools. No phylogeny or RNA tools.
Click here for a screenshot.
Subject: BioFOX for Firefox 
