The model that is most recommended is the Pioneer 206. http://www.pioneerelectronics.com/PUSA/Professional/Computer-Drives/BDR-206MBK
Another to consider is the LG WH10LS30K, which tends to be less expensive than the Pioneer.
Most modern computers will be able to work with blu ray drives. A dual core processor is recommended, as is 2gb of ram or more. You will need a SATA port on the motherboard, since all internal blu ray writers use the SATA interface. If your video card has hardware acceleration (Avivo for ATI or PureVideo HD from Nvidia), it will help playback.
Here in the US, the vast majority of blu ray drives come with the necessary software needed to play back blu ray video on the computer. This is usually a software package from Cyberlink and includes PowerDVD. Your system will need a video card or built in video that is HDCP compliant, and the monitor will also have to be HDCP compliant in order to play commercial blu ray disks. Cyberlink has a program to test your equipment to see if it is compliant. It is a free download and can be found here: http://www.cyberlink.com/stat/bd-support/enu/index.jsp
If your video card or monitor are not HDCP compliant, you could run AnyDVD HD, or DVDFab Passkey in the background to remove the need for HDCP equipment. Neither of those programs are free.