Does anyone use LXR?
cmars232: I used to a long time ago.  It was OK, but now I'd just use the Eclipse CDT.  CDT can probably cross-reference your code about as well as LXR if you tell it about your compiler & include paths.  "Jump to declaration" (F3) and call hierarchy (Ctrl-Alt-H) are among my favorite shortcuts for tearing into a new code base.I'm assuming you're talking about C/C++ here...  for Java, Eclipse or other IDEs would fit the bill.  For dynamic languages, you're totally screwed, you'll probably have to learn the codebase from lots of reasoning, strategic breakpoints and deep conversations with the interpreter.I prefer my magic F3...