Life on the Balcony is one I've just recently come across. Fern Richardson has great tips and ideas and she's also written a book called "Small Space Container Gardens" (which I'm on the library wait list for).
Another site I've been looking at is, Urban Organic Gardener. He has some really good recycle ideas for potting and caring for your little garden, like how to make a hanging herb garden out of empty soda bottles.
I'm excited for this weekend, as my mum has promised to show me some of the planting she has done and to give me some lessons.