If you ever had to deal with morphology in English, you probably found one or two libraries to help you out. But if you had to do that for Russian, than I’m sure you are missing a few hairs, and the ones that you still have are grayer than they used to be. I’ve got some good news for you though, now there is Morphos (GitHub repository).
Morphos is a morphological solution written completely in the PHP language. Supports Russian and English. Provides classes to decline First/Middle/Last names/nouns and generate cardinal numerals.
Just look at this beauty!
var_dump($dec->getForms($user_name, $dec->detectGender($user_name))); /* Will produce something like array(6) { ["nominativus"]=> string(8) "Иван" ["genetivus"]=> string(10) "Ивана" ["dativus"]=> string(10) "Ивану" ["accusative"]=> string(10) "Ивана" ["ablativus"]=> string(12) "Иваном" ["praepositionalis"]=> string(15) "об Иване" } */
Just this alone can make user interfaces and emails so much better. But there is more to it than that.