Get yourself this little tool right here: watto.org/extract/info.html
or this one: fmod.org/index.php/download
To let you know, the FSB file extension is a FMOD Sample Bank Format file. So best to go with fmod.
The first option involving opening the FSB file in its native program is preferable because it's both easier and will probably result in a more accurate file conversion. Of course if you don't have a program that opens FSB files, a third-party file conversion tool (the second option) could be very useful.
Important: You cannot usually change a file extension (like the FSB file extension) to one that your computer recognizes and expect the newly renamed file to be usable. An actual file format conversion using one of the methods described above must take place in most cases.
I guess the rest is up to you. Have Fun