Ukrainian Writing System (Omniglot): basic introduction to Ukrainian alphabet with addition information and language related links.
Ukrainian (UCLA Language Materials Project): an introduction and overview of the Ukrainian language, with links to related sites.
Ukrainian Language Education Centre (ULEC) (University of Alberta): provides resource materials for primary and secondary level teachers and students of Ukrainian language; includes classroom materials for all grade levels, K-12.
Online Dictionaries
Lexilogos -- search several different English-Ukrainian-English online dictionaries (Lingea, Cybermova, Slovnenya, Glosbe)