Yes. A trickle charge rate for the batteries is not going to be sufficient to charge your phone. So you will need to charge the batteries up before connecting your phone, and disconnect the phone when the batteries are depleted. You should be able to leave the solar connected while the phone is charging to supplement the battery output.
I performed some charges on a couple different types of smartphones (HTC Incredible, iPhone3GS, iPhone 4S) that had fully drained batteries and they charged to 45% - 50% battery reading. Is this typical?
That sounds quite good. Is that with 3xNiMH? People are reporting 20-25% with 2x alkaline cells on the current generation of smart-phones.