I think you can also use the Indo-European section of the Tower of Babel database, which is also based on Pokorny, but only with caution, since they sometimes depart from the mainstream interpretations quite a bit. Anyway, this is what you get if you manage to type faciō in the Latin search field. You can also try Köbler's Indogermanisches Wörterbuch, which "is based on the IEW and including laryngeal-based reconstructions, but only as alternative lemmas with cross references to the pre-laryngeal ones" according to Wikipedia.
I also wish there was a better online tool, and if I had some time, I would be happy either to create one, or help start it, at least.
Fortunately, the body of information concerning sound laws and developments is constantly growing on both Wikipedia and Wiktionary - you might want to try these articles for starters:
By the way, there used to be a free on-line source that is now hidden behind the paywalls. If your institution has access, though, you can check it out here. Note, however, that the Leiden school of linguistics may differ from the mainstream in some points.
EDIT: Oh, and I almost forgot about the indispensable TITUS, with lots of text samples, corpora, databases, grammatical sketches and much more!