As a gist, the new SQL Server 2012 will have a new set of editions:
– Standard – will be the new basic version
– Enterprise
– Business Intelligence
– Developer
(no more DataCenter, Workgroup and Standard for Small Business)

For licensing, Microsoft is doing away with per processor licensing – but replacing this with per core licensing (licenses to be sold in 2-core packs). And for a VM, you pay for virtual cores.

Cost breakdown nicely explained and tabulated by Glenn Berry here: http://sqlserverperformance.wordpress.com/2011/11/10/sql-server-2012-licensing-and-hardware-considerations/

Find the official transcript here:
http://www.sqlpass.org/Community/PASSBlog/entryid/380/Preparing-for-SQL-Server-2012-What-You-Need-to-Know.aspx

Link for Licensing Options for SQL Server 2012:
http://www.microsoft.com/sqlserver/en/us/future-editions/sql2012-licensing.aspx