Dahlias like the soil to be at 60* for planting- any colder & they'll sit there & rot- esp. if you get a wet spell. You can start them earlier inside in potting soil to give them a head start & then put them out when the soil warms up.
Ones that got left in over the winter have had a chance to get aclimatized & won't suffer as much as ones that are freshly planted.

I have started 3 dahlia plants inside, and I am not quite sure when or how much to water while they are inside. I watered them a little bit after I planted them, but havent watered at all since (about 3 days). I figured maybe once a week?

They don't need watering until they start growing, then just moisten the soil- don't overwater or let them dry out too much- about what you'd do for a house plant.

Well they have little green sprouts coming out of the eye(?) that are about an inch tall. Does that mean I should moisten them a little every week?
Sorry for being so ignorant on the subject, I usually kill every plant I try to grow. I am trying to improve though!

If they have little green sprouts coming out of the eye that are about an inch tall, then they definitely should be potted up. Then give them a good watering, put them under lights or natural sunlight, and watch them grow. Don't over water them. So after the initial good watering, I would let them go for about a week before watering again, but that depends upon the medium in which you plant. Don't let them dry out completely, but don't overwater. Watch the leaves. When they START to droop, they are telling you that they need more water.

Here is a link that might be useful: See other discussions about potting up.

Wow, that was awesome Jroot. Thanks! I potted them up (with newspaper! haha) and they are sitting nice and snug in my dining room.
I have seen a little bit about topping in here and I was wondering if it is recommended to "top" shorter varieties as well (one of mine is only supposed to get up to about 14 inches or so).

YAY -- spring fever here too! Can I plant my tubers in the same pot I will put them outside in? This board seemed to infer that they would be re-potted?

Thanks in advance! oh, but COULD I repot if I wanted to?

Of course, you can repot if you wish to. I usually do. However, if you have a pot big enough for them, and you don't mind lugging it in and out, as dictated by the local weather (NO FROST ALLOWED), then you could put them into a larger pot if that is where you want them to be for the summer. Personally, I find the big pots too heavy to lug in and out.