Here is a quick how-to outlining the process to create custom inkscape SVG filters to style text. The tutorial covers the procedure to create a filter for text with a shadow, slightly inset text and raised, super glossy text. The tutorial also has a downloadable SVG so you can open up the image in Inkscape and play with the filters yourself.
Although the newer versions of Inkscape (0.48 and later) feature a wide range of preset Inkscape filters available for use. (see Tavmjong Bah’s Book for examples of the presets). However, for advanced inkscape users, this is a great overview of filter creation that yeilds some pretty nice results. Note: the results above are my attempts at the tutorials.)