lwp is a lotus word pro file.
As far as I know, word pro file format isn't open and I don't know of a .lwp -> .doc converter (we have plenty of .lwp files at work from a time before MS Office was rolled out, and it can be a real pain). However, I've just tried opening a .lwp file in Word X and if you set "enable -> recover text from any file" then it's readable, if not pretty. Might be good enough if you just need to read it.
edit: BOAC's link is to a viewer, although it's for Windows not OS X. You can't edit the document, although it'll look much nicer than my method. Not much use without a PC though
