There are plenty of Mac tools for video compression in the marketplace, ranging from Windows Media-oriented tools (Flip4Mac) to professional workflow builders (Sorenson Squeeze) to hardware-assisted H.264 crunchers (Elgato turbo.264). Few of these products, however, have hit the sweet spot of wide-ranging capability, quality output and extremely affordable pricing like VisualHub from Techspansion. For less than $25, you got Flash and WMV output that rivaled products 3x the price, plus easy conversion to iPod and iPhone-friendly formats. Along with sister apps audio compressor AudialHub and iPod-only video converter iSquint, VisualHub was a prime example of a well-built, "Mac way" media app.
Sadly, the past tense above is no accident. Techspansion's website has been shuttered and the products have been discontinued. Tyler Loch (Techspansion's founder) let us know that the difficult decision to close down Techspansion is a personal one, and he's readjusting his priorities to focus on other needs. His choice is understandable, but we will definitely miss VisualHub (not to mention the laugh-out-loud funniest release notes in software history). Best of luck to Tyler in his future efforts.
Update: For those who are inquiring, there are no current plans to move VisualHub to open source. The underlying engine for much of the compression magic, ffmpeg, is already open-source and present in other Mac tools such as Handbrake.