I'll be brief, because I don't want to sound like I'm bragging: I keep a pretty pedantic list of all my inflows and outflows of cash, so it's easy for me to keep track of how much I spend on myself. A guilty conscience led me to think of a good way I can donate to charity and make myself feel better without feeling like I should give more - basically I donate 10% of any amount I spend on entertainment goods/services to charity. If you can track it, it's a good way to do it, because then you can say you're buying that new plasma TV so you can give 10% of the cost to charity, and not just because you're a capitalist pig!
Anyway, I mostly wanted to draw attention to the fact that there are a huge number of charities out there, to whom a donation of any amount would be welcome. So I would encourage people to find a charity that resonates with your personal beliefs (i.e. what you consider most important), and just give a little now and then.
One I found just recently (thanks to a BBC World Service Radio program) is something called
Gondwanalink - it's basically a concerted effort to obtain, restore and maintain natural bushland in the south of western Australia, such that there's a continuous tract of bushland that stretches for 1000km across the state. The aim is basically to preserve the extremely biodiverse regions found there.
http://www.youtube.com/v/vnS2QsNjawU&hl=enA site that has a big searchable list of charities in Australia is
ourcommunity.com.au, so have a search and find one you like, donate, and then go sit on the moral highground.