I gonna share my experience with getting it running under OSX.
My machine is an intel macbook with Leopard 10.5.7
I have ehrr... donwloaded a copy of Crossover, but ended up using a modification of it called Crossover Games (both 9.1). I don't think there is any difference, however.
So, first I opened my newly ehrrr... acquired copy of Crossover and opened the installer via "CrossOver Software Installer". It installed fine in a new xp bottle, but the Fonline 2238 Launcher (the only app that showed up in Crossover's application folder) did not run.
Then I tried running different exe's from the Fonline folder via "Run command" function (right-click on the icon of CrossOver in dock, choose run command, then chose the bottle from which you want to run an exe). Nothing worked, and the launcher returned an error asking me to install the windows version of Mono to run .NET exes or something like that.
Instead of installing Mono I went back to the "CrossOver Software Installer", and installed Microsoft NET frameworks 1.1 and 2.0 (it's under Runtime Support Components, crossover downloads them on its own; install in a new bottle).
After that running exes via "Run Command" worked. I could open Config.exe and Fonline.exe, however, I still cannot use the Launcher
The game runs fine, there are some distortions (apparently more of them in full-screen than in windowed mode), but overall it's alright.
So, that's my story. Hopefully, somebody will find it helpful.
BTW, yes, I tried using wine, but for installation it required XCode, and I lost my installation CD a long time ago and I am not a part Apple Developer Program (that costs 99$). So there was no legal way for me to get XCode and run Wine, so that is why I went with crossover. If I have to (ehrrr...) spend money, then I'd rather spend it on a working product than on a product that can help me run another open-source program.