About a month ago, I received a copy of "Beginning Spatial with SQL Server 2008" by Alastair Aitchison. I've become acquainted with Alastair through his frequent postings on the SQL Server Spatial forum (under the login Tanoshimi), where he's always been very helpful and patient with folks starting out with spatial data concepts and SQL Server practice. Although I'd been working with SQL Server spatial for a while now, I read the book from cover to cover. It doesn't disappoint. The basic spatial concepts are explained in the first few chapters, and he goes on from there to present an encyclopediadic approach to the spatial methods and properties supported in SQL Server 2008.
I especially enjoyed that he showed examples of geocoding, visualization, and services using both Virtual Earth and Google Earth. I also liked the scenario based approach to the spatial functions, for example showing STIntersection using the Appian Way and the Pontine Marshes. Each spatial function described has an example using real-world geographic use case, and this helps in understanding. The end-to-end examples gave you a good understanding about how to start off with spatial using import, query, and visualization.
The only quibbles I had were with the introduction to SQLCLR and object orientation WRT spatial. It was confusing to describe the OGC inheritence hierarchy without contrasting this with SQL Server's actual implementation (two data types geometry and geography each supporting all of the instanciable OGC types, like point, polygon, etc). And because SQL Server's .NET UDTs don't support inheritence, individual classes for each OGC type is not the way they're exposed (or even implemented internally AFAIK). I was also surprised at the assertion that you can't initialize a geometry/geography from a WKT string in T-SQL; this works because conversion from string implicitly calls the Parse method and uses the default SRID for either type. Reported it as errata. Finally, more performance-related information might have been useful, but the book was positioned as a beginning book after all.
Starting off with spatial data is more than just learning the intricacies of a new data type or lists of methods and properties of a SQLCLR-based type; you need to acquire some domain-specific knowledge to make heads or tails of the data type. And that's where this book is invaluable. I'd recommend it as a way to get up to speed quickly with the SQL Server 2008 spatial types.