It seems likely that the primary distribution method for Mac OS X 10.7 Lion will be the Mac App Store.
Apple Insider spotted a post on the fscklog blog that suggests that the developer preview of Mac OS X 10.6.8 includes updates to the Mac App Store to support the delivery of Mac OS X 10.7 Lion when it launches some time this summer.
Earlier this month it was first reported that Lion could be delivered through the Mac App Store with customers who were unable to access the Mac App Store - perhaps due to a slow or complete lack of internet connection - being offered the option of an optical disc.
Mac OS X 10.6.8 will also contain fixes for MacDefender malware and related infections, Apple promised last week.
It is thought that Lion has a minimum requirement of a Core 2 Duo processor, meaning that the earliest Intel-based Macs will not be able to run OS X 10.7. It is likely to be launched at some stage in the summer, with more details of timings expected at next week's WWDC.