"best practice" is not actually to avoid bed sharing. It is now becoming clear that for non-smoking parents with a breastfeeding mother (with other provisos such as setting up the bed safely for bed sharing, avoiding drugs and alcohol) bringing a baby into bed (or having a side along cot) actually helps to reduce the risk of SIDS. Breastfeeding mothers lie in a protective way with their infants generally as well. There is a huge ongoing study in Bradford looking at the differences between the ethnic community (more commonly alcohol and smoke free, breastfeeding and bed sharing) and the white British community (less commonly smoke free, more likely to drink alcohol, more likely to formula feed and separate sleep). The ethnic community's risk of SIDS is significantly lower and this is put down to a combination of these factors.
Check out isisonline.org.uk for more information to help you make the decision that is right for you.
Incidentally, many stats on babies dying asleep with their parents were totally skewed by factors such as including babies who died when their parents fell asleep on the sofa with them (ironically trying to avoid bed sharing) and babies got trapped in the cushions, or one study looked at SIDS deaths and counted babies who had died in their cots but had spent some time in their parents' bed as bed sharing deaths which really makes no sense. But these studies were used to make the older recommendations on not bed sharing.
The new research is with UNICEF and other trustworthy organisations.
In the end you need to work out what feels right for you, but understanding why guidance was one thing and what the evidence is now saying can be reassuring if you do want to consider carrying on bedsharing.
Here are some useful links.
neuroanthropology.net/2008/12/21/cosleeping-and-biological-imperatives-why-human-babies-do-not-and-should-not-sleep-alone/
www.uppitysciencechick.com/MorganGroerSmithSafeSleepJOGNNNov06.pdf
Also "Three in a Bed" by Deborah Jackson is a brilliant book about how to safely bed share and what benefits it has to you, and to your child's attachment and development.