For a prepaid visa, I recomment the Visa Buxx card from Wachovia. I heard about it last year on my local news around xmas.
It is geared towards teens. Parents can put money on it, up to $1,000 max at any time and view their spending habits. It is great so your child won't loose cash and also nice for gifts. Also great for children in college who still get an allowance.
There is a one-time fee per card, which isn't much. I have one for myself and just signed myself up as the teen. You can get alerts if they use them at certain ADULT stores that they shouldn't or block them (I'm pretty sure it can be done). You can also get alerts if it falls below a certain amount.
I put money on mine on a weekly and sometimes monthly basis depending on our financial status. I use mine for xmas spending and vacations and LOVE IT. Gives me a budget to spend with so I'm sure NOT to go over.
When DD becomes old enough, she will definately be getting one. I can track her purchases (to see if she uses it wisely) and put her allowance on it. Nice if they go away with family members.
If you have any additional questions, please let me know...