@nice gaijin: We used to write notes to each other in katakana English when we had substitute teachers.
For pronunciation, audio is important. Basically, recordings of native speakers (something like the audio files attached to the dictionary entries in WWWJDIC would be a possiblity, or something like
WEB版「エリンが挑戦!にほんごできます。」サイト閉鎖と新サイトのご案内 | WEB版 エリンが挑戦!にほんごできます。 ), where you know what they're saying, so you can follow along. Pay attention to vowel length - the difference between お and おう sounds, for example.
ETA: Regarding katakana, yes, it should probably be learnt second, I never said it should be learnt first (although in the long term I don't think it matters). However, it should be learnt directly after hiragana, while learning some basic vocab/sentences structures - it is not hard to learn some basic grammar alongside learning katakana. You don't have to learn one thing at a time.
Any basic textbook will introduce it early on since it will be probably used for things like: your name, your nationality, the town where you live (as part of self-introductions), and a great many common words.
It should definitely be learnt before you start on kanji.
Saying "learn hiragana, then katakana" I think generally anyone would agree with. To say something like "you'll rarely use Katakana" I think does a learner no help and is what I take issue with. You will certainly use katakana; even if you are outside Japan if you look at any Japanese website, at any reading materials, play any Japanese games, use pretty much any textbook, or any online materials that don't use romaji.