okay, let me explain, step by step how i did it.
first off, to achieve this i used a program called wineskin, wich is free to download from: http://wineskin.doh123.com/
after installing that, you have to update first, so open wineskin winery and click the update button, this will download the latest wrapper.
after that i added an engine, i used ws8wine1.3.1, yes that is an older version, but it is one of the most stable ones in terms of gaming, using the newer version will f*ck up the mouse (excuse me for my language).
you can add an engine by clicking the + button in your wineskin winery.
after that i created a new blank wrapper, wich can be done by clicking the button at the bottom of your winery window.
after creating that, and installing gecko (html is useful in my opinion), i opened it in finder.
right click the app you just created and click "show package contents"
that will show you drive c, preferences etcetera.
it also contains an app called "wineskin", open it.
now get your gta san andreas disk (or whatever you have, i used my disc), and put it in.
click on the install software button, go to your disc in finder, and select setup.exe.
now just install it like you would normally do on a windows machine.
after youve done that, it is usefull to nocd crack it, as wine does not connect with your mac disc drive.
im not going into cracking yet.
now get your mta installer from the internet.
in wineskin, click on install software and select your mta installer, install it just like you would do on windows.
after that, click the button in wineskin saying "choose executable".
browse to your mta installation directory and select multi_theft_auto.exe.
after that, do a little test run (there is a button for that).
you will get a few errors about fonts.
so download the following fonts:
tahoma.ttf
tahomabd.ttf
verdana.ttf
place those ttf files in: HOME/applications/wineskin/mta.app{show package contents]/c_drive/windows/fonts
test run it again, and it should work.
adding pictures soon.