For the lazies:
Says "Compatible with 6000, 9200, 9300, 9400" on the battery itself.
Problem is? They are so old I doubt anyone on SD would have one of these around.
Dell sold the 6000 in quantity though and they're still quite popular (just check eBay). The sound quality of the onboard audio system on these is still impressive. The M90 is a 17" hi-res beast with even better quality audio, dedicated video and, best of all an SATA interface so an SSD can cheaply breathe new life into them. Oldies but goodies.