Forge is still in very early stages and very buggy and mods would take time even if it was completely done right now. Do not expect modding on 1.8 in any real capacity until at least january.
Most likely no. There are differences in rendering between 1.8 and 1.8.1. You can try but you're very likely to get errors so I wouldn't test it on a world you care about.
New Mods 1.8 - 1.8.1 2014