The new lithium batteries really don't need a 24 hour charge (the booklet says do it) because once they are fully charged the stop charging and cannot be overcharged. You can go ahead and plug it in and use it immediately if you want. I just let mine charge until it was full, about 2 hours and started using it.
I picked mine up in the store and started using it right away, ran about 3 hours worth of errands using GPS and maps and of course playing with it. Then went home and plugged it in and played with all the settings and what not for a few hours while it was charging and I have seen no ill effects from it.