Welcome back!
I'm not actually doing a structured low GI diet (i.e. Rosemary Conley GI Jeans) but I am selecting my foods based on their GI rating. Basically I've stopped eating processed and 'white' foods such as spuds, parsnips, white bread, etc and I'm now eating lean meat/fish/poultry/dairy and porridge, berries, nuts, sweet potatoes, butterbeans (and other beans) brown basmati rice and low GI fruit and veg. I use it in conjunction with basic calorie counting - just so that my food keeps me feeling fuller longer. The best thing about it is that my husband loves the food so there is no hassle with preparing two different dinners as there has been on other diets - he just has more of it than I do.
I spent a day using Google to search GI information and found lots of good information in iVillage and a couple of Canadian and Australian diabetes websites. Rather than buy a diet book I bought a couple of Antony Worrall Thompson Low GI recipe books which are great as a jumping off point - both of them have a section at the front explaining the whole GI thing.
Good luck!