http://www.vmware.com/download/eula/multicore.html
vmware licensing is based on the number of Sockets in the box...not cores.
Here is the short breakdown in licensing requirements.
esxi free- 4 core support only.
Software Licenses with six(6) cores per Processor restriction: vSphere Essentials, vSphere Essentials Plus, vSphere Standard and vSphere Enterprise
Software Licenses with twelve(12) cores per Processor restriction: vSphere Advanced and vSphere Enterprise Plus
Microsoft licensing - depends on the day :o)
This is your best reference. - http://download.microsoft.com/download/E/E/C/EECF5D44-9A88-43D8-AFDB-D2AB82BE035C/Win%20Server%20Lic%20Book%20customer%20hi-res.pdf
Windows Standard - for every license you get a single VM.
Windows Enterprise - for every license you can run 4xVM's
Windows Datacenter - you license every Socket in the box (like VMware) - Run as many VM's of that product family as you can (ie, Windows 2008 datacenter allows all Windows 2008x flavors). I am not positive is a Windows 2008 R2 allows you to downgrade to Windows 2008 flavors as well. I'd assume so.
My recommendation - pony up the cash and get datacenter and then laught if Microsoft comes auditing because you won't care.
SQL 2008 licensing - Read the information carefully - it changes and is confusing. Best to call Microsoft licensing to be positive.
Hardware Capabilities
http://www.directionsonmicrosoft.com/sample/DOMIS/update/2008/02feb/0208ws2plp_ch.htm
Vmware limits - you can only create at max an 8 CPU VM. However If you need that many cores..rethink it's virtualization acceptability. See #5, then read it again.
Now, just to throw in the standard best practices and answer the questions that I know you are going to come back and ask.
#1 - No, there is no USB support in a VM. you can't attach an external disk to your VM. Look at IP/USB devices for solutions for that.
#2 - If you create a hardware RAID Array larger then 2TB it will not work. Each Virtual disk/LUN/Array/Containter (whaever terminology you want to use) must be smaller then 2TB-512bytes (Use 1.99TB to be safe). RDM also cannot be larger then 2TB. For larger I recommend using ISCI initiator inside VM.
#3 - The recommendation is to try to stay in the range of 10-20 VM's per VMFS volume (many busy VM's can cause scsi reservation issues). This has gotten alot better so you can push the limits (wait for RParkers response when he see's this :o) )
#4 - You can create multiple VMFS volumes and Join them together to make a larger VMFS volume. Highly not recommended
#5 - Best practice with virtualization - forget what you know about resource allocation. Start a Windows 2008 VM with 1GB/Max 2Gb of RAM and a single CPU. ONLY increase CPU/RAM after determining you must. The less multiple CPU VM's the better for scheduling
#6 - Average oversubscription is typically 4-5 VM's per Core, but of course this depends on load and SMP VM's
#7 - Don't ask Best Backup solution (this start a war) - Your typical responses are going to be Vizioncore, Veeam, esXpress as the 3 primarys with scripts and a smattering of others mentioned (like VDR). Try them all (that way you can get backups and not pay for at least 90 days :o) )
#8 - Don't freak out of your Windows 2008 VM's cause you to use up all your host memory right away. Until you use up all the memory, the VM's will uuse large pages (which is good for performance). Once you oversubscribe too far, they will all switch to 4k pages and your memory usage will drop dramatically. After that, when memory is maxed...you are done..go no further :o)
There are litterally hundred more, but if vmware would make these tips here sticky'd we'd probably have half as many threads and alot higher quality content. Of course, #3, #6, and #7 will probably cause a debate already. I appologize in advance.