It doesn't read .doc, but it does read .rtf, and any program that creates/reads .doc files should be able to convert them to .rtf. (
AbiWord, if you don't have another one, is free and tiny.) They'll very likely be bigger files. And they'll need to be set at a much larger font size than is useful for print--I prefer 17pt font for reading on my 505, but many people prefer 20pt; I'm partial to small text.
You can leave them at 12 pts, and they'll be very very tiny, and just use the M or L settings to read with.