Jessesgirl,
In Australia, the guidelines that are STRONGLY encouraged by nurses and midwives and medics in regards to babies are:
* keep their head uncovered.
* have a firm mattress, and only one (sheepskins, soft ones aren't recommended).
* Wrap tightly (sleeping bags for babies are strongly recommended, that have the arms free for movement, but the legs are in the 'bag' - if that makes sense). There is a good technique for 'wrapping' (it's like swaddling, but keeps the head free), that is safe for the baby and keeps them lying on their backs, rather than rolling on their fronts/side (which increases the risk of smothering/choking).
* Lie them on their backs at all times.
* Keep their bed free from toys/pillows/things that 'position' the baby - as these can increase the risk of smothering.
Babies can overheat pretty quickly, so most recommendations mention only the sleeping bag, or a light muslin wrap/blanket at most. Room should be kept around the 25 degree mark - and there should be no more than one 'cover' on bub. And smoking is bad for babies - which goes without saying almost (so basically, keep them free from smoke as much as possible, especially with regards to immediate family and your own home/car).
This is the recommendations from SIDS&Kids Australia. I just sat through the course over the last couple of weeks - hence me knowing a lot!
For more info, you can look at
http://www.sidsandkids.org/safe_sleeping-parents.html for the basics. From this site you can also download pamphlets on things such as 'what constitutes a safe sleeping environment in regards to mattress/toys/pillows'
Hope that helps!
Sasch