[sarasi]

I'm afraid that packetpirate's sentences are not correct, although it was a good try. The second one has the wrong particle and is an order rather than a statement, and the first one also has the wrong particle and is in the future tense rather than present.　『かたかなを勉強しています』 would probably be best (it's more natural to use benkyou shiteimasu rather than naratteimasu in this situation).

I have written katakana in hiragana (かたかな) above, but you could also write it in katakana (カタカナ) or kanji (片仮名) if you wanted. Actually writing katakana in katakana seem to be the most common these days.