I used the online Royal Horticultural Society pages for info on plants mostly, and a small guide to wild flowers Collins one to identify plants while outside as it goes in the pocket. So get a good pocket one to make sure you are picking the right stuff.
I also used a lot of other internet sites including ones for horses, rabbits and other plant info sites and chemistry sites as well when working out what piggies could and couldn't eat. There will be the second part of my 'good green forage' guide in the january edition of the Guinea Pig magazine, which gives the most common useful ones and also some useful pictures. I didn't find a good 'what piggies can eat' foraging book just a list or two online and some of those were incorrect and I wasn't the only person looking, which is why the magazine asked me to do an article for them. If anyone does know of a good book like this I would love to read it too!
