Level of politeness: "oshiete kure" is rather a command, only usable among close friends.... or the yakuza. ;) "oshiete kudasai" is the normal level of talking. "oshiete itadakemasu ka?" is nice and polite talking.

"oshiete itadakemasen ka?" is nice and polite talking.

"oshiete kure" sounds strong and not polite at all. and it is used by boys but not many people use this. "oshiete kudasai" is polite way to say like "please teach me",i think.