I tried this and it really works. It is such a good deal for baseball fans, I just can't beleive it. I first heard about it from reading a post by an old friend of mine David at the USS Mariner Blog. I'm going to post his article here:
It isn't every day that a deal comes along that is such an easy choice that you feel compelled to make the purchase just based on the ridiculous value you're getting for the money. Today is one of those days, so as a service to our readers, here is something I discovered this morning while shopping through MLB.com's subscription packages.

Since I reside in North Carolina, I was considering dropping the $80 to buy access to MLB.tv, which would allow me to see some live Mariner baseball this year. $80 is a bit steep for watching through questionable connections on my computer, however, so I was surfing for alternatives. I was hoping to find some package that would also give me the condensed games, so I could watch the west coast games (which begin as I'm heading to bed) the next morning. While going through the subscription options, I found this page. It presents three options:

1. Purchase MLB.tv, which allows you to watch a large majority of games live, but no condensed games or optional footage, for $15 per month or $80 for the season.

2. Purchase MLB All Access, which includes MLB.tv, plus gameday audio, condensed games, video highlights, and some other fluff that I probably won't use. This is $20 per month, or $110 for the season.

3. Sign up for MSN Premium, which, near as I can tell, is a bundle of free programs that Microsoft is selling as a subscription model for $10/month. Newsflash, folks: Pop-up blockers, spam filters, and email accounts are free. Don't pay for them. But wait, MSN Premium includes MLB All Access. Hey, thats promising. And its $10 per month, rather than the $20 per month if you buy directly from MLB.com? Already sounds like a good deal. Hey, why not just throw in the first 3 months for free, just for the heck of it? Wait, they do.

So, you can pay $80 for 6 months of MLB.tv, $110 for 6 months of MLB All Access, or $30 (3 months free, 3 months paid) for 6 months of MSN Premium, which includes MLB All Access. You don't have to be a math major to figure this one out.

Seriously, $30 for what MLB All Access is offering is a steal. Go sign up now.

The only thing I would add is that this is a good deal for those who are outside the regular broadcast area. For instance I am a Dodger fan is Seattle. The games of your local teams are blacked out, so you can;t see the Mariners in Seattle, etc... Oh, and don't forget to cancel your subscription in six months.