While \"charset koi8-r\" in ~/.gnupg/options is supported, cp1251 is not. Because of this, it is impossible to generate a correct key with Cyrillic characters in the user info when using a CP1251 locale (e.g. ru_RU.CP1251). Displaying such info for keys generated by others also does not work.
gnupg >= 1.2.0 should address this issue; please let me know if not.
CP1251 still does not work with gnupg-1.2.1-alt1. util/strgutil.c contains support only for utf-8, iso8859-1, iso8859-2 and koi8-r charsets; cp1251 is missing.
I'll try to not forget this while preparing gnupg-1.2.4.
Ok, patched in gnupg-1.2.4-alt1.