Are typos valueable? For instance for a big company like Google. If the letter that is mistyped is next to the key that the proper letter is meant to be, could this be of any value. I mistype all the time.
Mistypes of Google and other corporations will be taken away from you. Many companies work to protect their trademarks and typos are considered cybersquating. You might get away with it for a while, but you would get a rep as a cybersquater, which would hurt your case if you had another TM issue - even if you were in the right on that one. Typos of generic, dictionary words / phrases are fair game, if you are not pretending to be another company. More discussion here: http://forums.digitalpoint.com/showthread.php?t=665433
domain typos aren't valuable if you're trying to sell them, but if you're keeping and park them you'll surely gain a couple of money. i think almost all google typos are taken but you can try with lower sites too. you can also try that "www" trick. that's buying a domain like wwwgoogle.com because a lot of times people forget the "."
I'm not an expert on this topic.. or anything thing else for that matter but a mispelled name is not very attractive and not very professional... so is it valuable? I think the answer to that is yes and no... Yes if its a often searched for name and you only plan on having it parked while earning money... and NO if its for a business.
Typos that aren't related to a company name i might consider, but rarely. It is not professional as someone said and you'd probably be wasting time developing a site on a mispelled domain. Resale value is another matter.