Yeah, there's material on Innsmouth scattered all through many of the CoC rulesbooks; I'll see what I can dig up to point you towards. (And, as mentioned "Escape from Innsmouth" should still be findable, either in bookstores on online.)
Also, if you have an Xbox, I'd HIGHLY recommend the "Dark Corners of the Earth" disc; it's set nearly entirely in Innsmouth, and really suceeds in capturing the feel of HPL. (It's also backwards-compatible with the 360.)
Be warned, it's a LONG, TOUGH game, though, but really rewarding. (And some of the parts could easily be translated to an CoC session.)
And, while not Inssmouht-specific, the modern-day Cthulhu adventure "Nocturnum" (available in D20 or BRP) features a cool scenario where the PC's are battling Deep Ones atop an oil rig. (It's a little OOT, since Dagon himself makes an appearance, but overall, it's VERY cinematic, and cold likely be worked out as a one-shot scenario.)