Well, don't install it just yet! Particularly if you are running the latest firefox release version Firefox 3.6.13, as last week alone the skype toolbar crashed firefox over 40,000 times. Yup, that's enough for Mozilla to officially block the new toolbar add-on too.
Skype & Mozilla are in talks right now to try to get it fixed, so best hold off until they come out with a new version.
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