I am working on a web mapping demo for a customer and I tried to reproduce the look-and-feel of Google Maps.
It is not yet perfect and things are still missing but I believe it is on a good track. If anybody interested I publish SLD (Style Layor Descriptor) files for download. Everything here is done with open standards from the OGC, thanks to GeoServer and PostGIS (BTW, everything on a Mac).

Click for fullsize

Of course my dataset is not as perfect as the one from Google so you can see some inperfections on the result.
Some details and explanation before you download:

• I have each type of data in one postgis table in EPSG:4326,
• For streets, I have street, avenue and highway in one table with an attribute to differenciate them. In that case you must adapt the criteria in the filter part or split the file into several if your dataset is different,
• You probably need to modify the maxScaleDenominator and minScaleDenominator to adapt to your dataset

Download version 0.2

Here is a snippet of one of them (for the land).

Any comments or improvements?