Volume Name Icon Reader is a (very) small tool capable of reading the image file Mac OS X will use to display the volume name when booting with the alt key down. You can see this article for more explanations.
Type the following in Terminal (this is innocent: it will just copy a file on your desktop and make it visible):
cp /System/Library/CoreServices/.disk_label ~/Desktop/file.vollabel
chflags nohidden ~/Desktop/file.vollabel
Then just open the file file.vollabel
on your desktop (after installing/compiling Volume Name Icon
Reader on your machine, indeed!).