It may be a little too basic for what you're after, but I have a couple of excellent wallcharts made by Kumon. They're intended for wee Japanese babies, and are waterproof so that they can be stuck in the bathroom, which is very cute.
They are, though, ideal for learning the Katakana and Higarana. Start off with the Katakana one, because the romaji is provided for pronunciation of each Katakana. The Higarana uses Katakana to show the pronunciation, so you need to be fairly competent with your Katakana before using the Higarana one.
I can't point you at a reseller without knowing what country you're in, but if you google "Kumon wall charts" or "Kumon bath chart" you should find them.
Once you've got the kana under your belt, Kumon also do a kanji wallchart
