Uninstall Lua from OS X 10.6.8
Based on my reading of Lua 5.0's makefile, I'd say:


Run make echo, and note the folders INSTALL_BIN, INSTALL_INC, INSTALL_LIB, and INSTALL_MAN
For each file in bin, remove that file from INSTALL_BIN
For each file in include named *.h, remove that file from INSTALL_INC
For each file in lib named *.a, remove that file from INCLUDE_LIB
For each file in doc named *.1, remove that file from INCLUDE_MAN
Upgrade to Lua 5.2 so if you accidentally install again, you can uninstall  :-)


Alternatively: if you download Lua 5.2 and configure it in exactly the same way (so all the INSTALL_* folders are the same), then its make uninstall will delete almost all of these for you.  You only have to delete liblualib.a from INCLUDE_LIB.