Bethesda's saying that it will be in the stores by Friday, so perhaps a shade later than May 1st, as promised--but not by much. I understand the strategy guide is already out. I only hope it's all-inclusive, since it is being written by people intimate with the product.
In general, I wave my privates in the faces of the aunties of strategy guides.
They are for the most part true garbage, written by authors who are usually still using very early builds of most games, without accurate information, and planned for release on the same day as the product, itself. I made the mistake, for example, of buying Prima's strategy guide to HOMM IV--the least time I will do that. Half the guide was literally a larger scaled representation of information already in the manual. There were no opinions offered, and it was clear the "author" had never actually played the game. Fortunately, the PR person at Bethesda Softworks was invovled in Morrowind's strategy guide, so I suspect it will be a good one.