to add a bit onto the gaijin explaination...
Jin is a suffix that means 'persons' or 'people', so Australians are literally 'Australia-jin', japanese are 'Nihonjin' (Nihon = Japan), english are Eigo-jin... add 'Gai' which (afaik) 'outside', and you have gaijin, meaning 'outside people'...
I'm doing japanese as a subject for my uni degree, which I'm doing externally at the uni I work for... I've always been facinated by the jap culture, and learning the language is a complete eye opener... sounds a bit fruity, but it's very rewarding... but I'm still learning, and some of it is challenging... Nihongo ga sukoshi hanashimasu.
I'm hoping to get an IT job in Japan, but I'm being realistic... from the stories of racism and hyper-compeditive job markets, it may be difficult.
Edit: Some more on the gaijin thing... you've got 'gaiteki' which translates to both 'outside' and 'foreign enemy'... so I guess you could say that (like a lot of stuff in japanese) it has several similar meanings... outsider, foreigner, alien, etc.