I was recently given a trial subscription to www.time4learning.com and I have been extremely impressed. Both boys have enjoyed it, but Tyler has really taken off with it. He is constantly asking if he can work on math and phonics and has done many of the science modules more than once and recites facts he's learned regularly. Some of what I've had them do is review, some of it matches what we are doing in our other work, and some of it is new. I've been impressed with it for all three types of learning.
Basically, Time4Learning (http://www.time4learning.com/) is an online homeschool curriculum for Preschool through 8th grade that covers math, language arts, some science and some social studies using games and animation to teach and reinforce concepts. My initial reaction was that it was quite expensive for an online resource ($19.95 for the first child, $14.95 for each additional child), and since I limit my kids computer time, I wasn't sure if it would be a good value. But the timing has been nice, coming just at the end of a pregnancy and when we are adjusting to a new baby. It has been really nice to just let the boys "play" on the computer and know that they are learning and doing school. The program is set up so you can subscribe one month at a time, so in my case, I think it will make a great supplemental resource for times when life is a little crazy.
The sign up process was easy and both boys seemed to be placed at the correct level. Ryan did think some of Tyler's activities looked more fun and wanted to do Tyler's level too. The program is set up to have learning time followed by playground, or game time. Tyler's lessons were engaging enough and fun enough that he never went to the playground. He especially loved the activity where he got to shoot a spaceman at the sight words. For Ryan, his lessons were a little more work, so the playground was a fun break. (And it was fun to watch him learn to play PacMan).