AerialX clued me in to Mono. I got the source to NUS Downloader from here: http://code.google.com/p/nusdownloader/ I recompiled with dimensions to work for Mac OS X. With the original source it looked like this: http://kimag.es/share/65504290.png With the modified source, we're in business: http://kimag.es/share/63914874.png I then packaged the exe into an app. No more WINE and it's 711MB version, this one is all of 98kb. You can't get much smaller. NUS Downloader for Mac OS X There are a few issues which I need to fix. First off, you need key.bin, which is illegal to distribute here. You place that key.bin file here: (ctrl+click or right-click on the app file and select "Show Package Contents" if you're confused) NUS Downloader.app/Contents/Resources/key.bin Second, it crashes when it tries to download. I'll get on that later, but for now, here's the initial release. As Eric Raymond said: release early, release often.