I'm looking for something to replace Visio on a Mac. I am getting tired of using VMware because it's too slow on my computer and was wondering if there's anything out there I can use to wireframe apps specific to Macs.
Even if the need is not exactly the same, some answers of this recent thread may apply.
I have the same problem, Visio and MS Project are the only things i can't find good replacements for, so i have an XP VM running in Parallels.
Most of the time we use the free version of Balsamiq. We have a license for the installable version, but no one uses it, preferring to use the online version.
Not as clean as Omnigraffle or Visio, but works well for wireframing.
Also, consider the Drawing tools in Google Docs, they are excellent and have all the basic shapes.
Not the exact answer, but Crossover Mac claims to run Visio 2K3 (And the whole Office Suite) using an API comparability layer, rather than a full-blown VM.
It's basically Wine with a pretty GUI and some Mac-Specific Tweaks.
OTOH, if you're feeling adventurous, you could try straight-up wine, whough it will likely require some console trickery.
The easiest way to get Wine on OS X is probably MacPorts -
sudo port install wine winetricks
But, if you find OmniGraffle too expensive, you can save some money and use Keynote ($20 in the App Store) with Travis Isaac's Keynote Wireframe Toolkit ($12), which I've found a very capable replacement. Check out his Keynote Kung-Fu presentation on the subject of wireframing with Keynote.