We planned on co sleeping from the start and read Three In A Bed for practical tips and safety information. We got a cheap side car cot from Ikea - the Gulliver has two heights and one side comes off. We used a rolled towel on the other side of the cot mattress to shove the two mattresses together. We were like this until he was pulling himself to standing, so we dropped the cot base and removed our bed frame so it was just the mattress on the floor.
When we have DC2 we plan on buying a king or queen size mattress for us three, with DC2 doing what newborn DS1 did originally - in the sidecar cot in a sleeping bag, next to me. In the early days I wore a cardi to bed and kept our duvet around my waist but the additional space in the side car cot and the fact that DS1 was in a bag kept things very safe.
There's some downsides to co sleeping - creeping in of an evening to go to bed (though you have to do that anyway if you follow SIDS guidelines of having them in the same room for up to six months) and sometimes I think I wake DS up. But I don't really know who wakes who up and the middle of the night feeds have been awesome. Literally roll over, latch him on, fall back asleep. I've no idea how people physically get up out of bed to do night feeds.
We have a regular routine - dinner, massage, cuddle, story, BF and then mobile in side car cot, then down to sleep for the evening. Then I join him around 11. The positives far outweigh any inconveniences for us. DS is now 14 months and rolls into me, literally demanding to be spooned. It's lush 