Given the recent bugs that developed for users in OS X 10.6.8, a number of people have wondered whether they will need to update their Snow Leopard installations to the latest version before installing OS X 10.7 Lion. Apple's latest Snow Leopard updates have included tweaks to the Mac App Store that specifically mentioned they were for the pending Lion release, and this has introduced a bit of confusion as to whether the OS install will require the latest OS version or if you can get away with using any version of Snow Leopard that has the Mac App Store.
It appears despite speculation, that the later of the two is correct, and you will be able to install Lion using any version of the Mac App Store. Apple's software requirements listing in the Mac App Store show that OS X 10.6.6 or later is required to install the software, which means any version of the Mac App Store will work.
While it appears Lion may work just fine with early versions of the store, do keep in mind that Apple did specifically update the store to increase compatibility with the Lion installation. Therefore, even though you may be able to get away with using an earlier version of the store, you might also consider briefly updating your Snow Leopard installation to OS X 10.6.8 before downloading and installing Lion.
Back up your data with Time Machine or a system clone
Use Software Update to install OS X 10.6.8
Reboot and ensure that everything is running correctly (do not worry about recent printer configuration problems with the 10.6.8 update, as these will change with the Lion installation)
Configure the Mac App Store, and download and install Lion
NOTE: Before installing Lion, considerof Lion for troubleshooting and maintenance purposes.