There's not really a universal tool for unpacking .resource files. What you're going to want to do is examine the file in a hex editor for a known file header type (almost all cases of Unity games use FSB, which starts with a FSB5 header) and use the Advanced Cutter option to extract every FSB file from the .resource file. Here's a few screen shots to illustrate this:
http://imgur.com/UzPgLW9
Select .resource file
http://imgur.com/LjdsGwE
Open in hex editor of choice (I like HxD personally) and find file header that identifies the file type. (this example is only for FSB files, there are many other things this could be, but for the purposes of Unity games it's almost always FSB)
http://imgur.com/lNBlRiA
Select the following options in VGMToolbox under Advanced Cutter and drag and drop your files to search them for all instances of FSB files and save these files as .fsb
After you extract the FSB files, Use fsb_aud_extr with the following batch file script (make a file named fsb.bat) that will convert all .fsb files to .wav (FSB files and the program must all be in the same folder for this to work, otherwise you have to put absolute paths in)
FOR %%a IN ("*.fsb") DO ("fsb_aud_extr.exe" "%%a")
Sometimes, the FSB files are stored in the .assets files which there is a Unity extraction script made for QuickBMS that will extract the files directly to .fsb, sometimes with an identifying filename. Otherwise, you gotta do it with the above method and the file names aren't very descriptive, but hey, at least you get the music.
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