Hey guys, this is just a quick little batch file tool I made this morning that allows you to easily switch your minecraft version between the current update (1.2.5) and the weekly snapshot (12w22a). All you need to do is put both the .jars in the .minecraft\bin directory and then choose either one and rename it to either "stable" or "latest" depending on which one it is. When you open the tool you will be told which version you are currently using and you'll be given the option to either "switch" or "exit". You choose which one you want by typing it and hitting enter.
Sorry if there are any bugs or problems, I didn't spend very long on making this so please post if you have a problem and I'll do my best to fix it.
If anyone has any questions about the weekly update or wants to know more check this thread.
Update:
I have updated this now and it's much better but will probably not release it unless people show any interest in this. If you want to try it out though you can PM me.