Most people agree that if you do it safely, i.e no massive douvets and pillows floating about, no smokers/drug takers in the bed, no gaps for babies to roll into, you are curled around them and the only one next to them (as mums alone have the instinct not to rollon them).
There is eveidence to show that it not as safe AND evidence to show that it much safer and it actually reduced cot death risk. I dont theink there has ever been a study comparing babies sleeping in cots vs babies co-sleeping in a text-book safe way, so babies that die for unknown reasons in cots are being compared with babies who have died as a result of unsafe co-sleeping practices. So there is no cut and dry answer, but its worth considering that in China for example (where co-sleeping is taken for granted) cot-death/SIDS is so rare there isn't even a word for it yet here in the UK 500 babies a year die in that way.
Here's an article I read on co-sleeping about a recent study by neuroscientists showing that co-sleeping is hugely beneficial to babies.
www.timesonline.co.uk/article/0,,2087-2179265_2,00.html
This is good to read too...
www.attachmentparenting.org/artbenefitscosleep.shtml
I was chatting on mumsnet about co-sleeping a while ago and someone said, "co-sleeping is the tried and tested method", which is so true because thats how we have all slept for millions of years.
'Threee in a Bed', is a famous and well-writen book on co-sleeping that should re-assure you. You could always start a thread on mumsnet for support on co-sleeping and I'm sure you would have allot of posts from mums that do it and think it is great.
You could always do a mix of cot and co-sleeping. That can work well too.
Hope this helps.