I don't use sketchup, but after hearing about extrude having an OBJ exporter, I decided to search.
I found this importer on this forum, but you need an account to download, but luckily, there was a direct download on the blog that held it.
Also, there's a hacked version of too that exports textures.
Installation and other infoDirect download-Normal Exports models with screwy textures.
Direct download-Hacked Hacked to export with good textures.