Not sure what LarryC is talking about. I have had no such problems with OxiClean, even leaving bottles for up to a weak, and I don't have the slightest idea why he seems to have a problem with floating bottles - seriously, if you find that you're having trouble ensuring that bottles sink, you're doing it wrong.
But it sounds like the residue possibly an issue with the cleaner not being fully dissolved (even if you think it is!) This can be a result of using too much, or mixing it with cold to lukewarm water, or even if your solution partially evaporates. OxiClean works best with hot water, and dissolves easier, so mixing with hot water is highly recommended. Also, the amount called for by the directions is overkill in most applications, homebrewing and otherwise. For the purposes of cleaning bottles and other equipment, you really only need less than a quarter what's called for, and in addition to dissolving and staying in solution much more easily, it saves a fair bit of cash as well. Lastly, use a lid on the vessel you use for soaking the bottles in OxiClean, especially (but by no means ONLY) if you live in a very hot and/or dry area, since evaporation can leave crud on your bottles and equipment.
Really, the only weird (though I would argue good( thing I've noticed by leaving bottles in OxiClean for a long time (and even overnight, but not as severely) is that the "label" on bottles which are directly printed on instead of having a glued-on paper or foil label (e.g. Corona) get ruined, and can continue to be messily rubbed out a fair bit after pulling it out (sexual innuendo not intended). After cleaning several of times, these labels probably disappear entirely.
You may wonder why I choose to use Corona bottles, and it is this: I bottle a single beer - the very last bottle - in a clear bottle for every batch. The reason I do this is to monitor clarity, and I fill it last because the last bottle, filled with only the bit of beer left at the bottom of the fermentor, will suck up the more trub and yeast than any other bottle, 99% of the time. Which means I can really rely on it to tell me when all my other beers clear up, since the one in the transparent bottle will, if anything, be the very last to fall clear.