Andrew - I am unsure what version you're using, but in addition to what has already been suggested, consider using the VLIDE's Apropos functionality... It's not 100%, but it can help with certain Methods/Functions again depending on your version.
Autodesk Exchange does a good adequate job of making Developer Documentation available online; sadly though the VBA documentation is not among that lot. Either keep a copy of the necessary acad_##_dev.chm (and others), or use VBAIDE docs.
HTH