E.T.
Hi - real quickly... mine started sleeping through the night (by that I mean 7pm - 5am) at about 8 months old. By 4 or 5 months old they were sleeping from 7pm - 5am with one middle of the night feeding, but that was pretty quick and they went right back to sleep. Then around 12 months they dropped a daytime nap and slept from 7pm - 7am. They kept that up until about 3.5 and now go to sleep more like 8pm.
Mine were not breastfed, but they were fed exclusively breast milk - I pumped for a year but could not breastfeed.
They shared a crib until they were 5 or 6 months old and then we moved them to their own cribs, next to each other. They have never slept in separate rooms - they learned early to sleep through each other's cries. It got worse around 2 when they wanted to get out of bed and play with each other - until then, no problems sharing a room.
Advice? Hmmm... put them to sleep early in the evening. Don't try to do a 9pm bedtime hoping they'll sleep later in the morning. It just doesn't work. Stick to your schedule. The better routine you get on, the easier it is. Don't worry if you have to nurse to sleep, rock to sleep, have them sleep in swings, etc, when they're little. You won't be doing that when they're two.
Good luck to you in dealing with two babies that need to sleep! How old are your twins? (and congrats on having twins, of course)