Two updates, of a sort: First, Maria Ramos has been kind enough to translate the makeztxt usage page into Spanish. The translation is available at Webhostinghub .
The second point is that it should be readily apparent at this point that there is no Android version of Weasel. Unfortunately, I just haven't had any time to work on it. As a good substitute, I would suggest using FBReader. It is also Free Software and has support for both many different document formats and many different platforms including, of course, Android. It lacks some of the display options available in Weasel, but it has nearly every other feature you could want. One feature that is noticably missing is support for reading zTXT or PalmDOC format documents.
I should like to mention that most Palm OS devices, even those with color and higher resolution screens, typically have much longer battery run-times than even the best smart phones. Because of this, a used PDA put together with Weasel Reader still make an excellent combination, not to mention being much less expensive than either phones or dedicated ebook hardware. Keep it in mind.