I would have gone over for a gap year before university, as I know immersion is the best method to learning a language, but I decided to go to Uni straight away. I don't have time for classes, with work and whatnot. And I'm sure it would end up costing a bomb.

Failing these, what would be the best method to learn? Recommendations for audio tapes/textbooks?

A found a torrent a few months ago with audio, books and everything I needed. It was great, just search for "Learn japanese torrent" on google and you'll probably find it, to my surprise the first audio lesson actually worked- and I suck at languages.

4 days after starting japanese I know the hiragana(not perfectly mind you, but I recognize almost all of it now), about 60 kanjii, and I havent started the katakana, but I probably will later today. The secret? James Heisig. Remembering the kanjii. His books should be in that torrent kenshiro mentioned. He doesnt teach the kana in order, rather he teaches them by groups of letters that look similar(the same way I learned the arabic alphabet), but then he also throws in some mnemonic devices. You can learn the syllablries in a few hours each if you're determined. The kanji are another story but his method is best too. He's better at teaching japanese than the japanese teach their own children! Give me a few days/couple weeks and I'll recommend what audio course you should use. As of right now I told myself I wouldn't learn much speaking until I got the 2 kana down first.

Also, if you have a good aptitude use this site to your advantage. http://www.guidetojapanese.org/start.html Rather than merely translating phrase to phrase from japanese to english, without understanding the core mechanics behind it, this site tries to get you into the "Japanese way of thinking." To learn to express yourself in japanese, you have to get used to a different word order, different way of describing things, learn how to hold a conversation where words get omitted as they become more implied, and the language changes to 4 different stages of politeness, etc. This site teaches all that well. Stay away from garbage like rosetta stone.

for a long time now I use http://japanese-online.com/, and podcasts from http://www.japanesepod101.com/ to learn how to speak. some things at j-list (http://www.jlist.com/STUDYAIDS/) helped lot. just by looking at the toys you get a feeling for the culture and therefor language too. but you will never be able to make the right pronounciation to differentiate between insults and politeness if you don´t talk to a native ..