Yes. When you open an account you will create a link between your online savings and another account - typically your checking account - and then you can transfer money back and forth.
Based on the amount you have to start with and the fact that you are new to this type of online account, I would recommend Amboy to you. They are paying 5.25% APY and have a simple opening process and easy to use, if spartan, web site interface for handling your account. I helped my parents set up an account with Amboy and they are very happy with it. Here is a link:
Amboy Direct: Premium Savings
If you decide instead to go ahead and open an ING Direct savings account, don't forget to utilize one of the links on this forum in order to gain a $25 new account bonus. While ING is only paying 4.40%, they certainly have a fine web interface and you shouldn't have any problems with them either, so the bonus is nice. Here is a link to that information:
SavingAdvice.com: ING Bonus Links
Overall, my suggestion would be to go with Amboy. The better rate is significant in my view. Still, I don't think you'll be disappointed with either.