It's September 2011. We just installed SharePoint 2010 Enterprise RTM. Want to install SharePoint 2010 SP1. Do we need to install SharePoint Foundation SP1 first? And should we install June update even though SP1 we are pulling is from late June 2011?
The guidance and "best practice" up until the August 2011 CU is to install SPF Service Packs and CU's on Server edition. From August 2011 the packaging process has changed and you only need one package to install.
So in order to install SP1 + June CU do this: (the Microsoft recommendation is to install June CU directly after SP1, there are a couple of nasty regressions in SP1 that you probably don't want)
In order to install SP1 + Aug CU do this:
Better be safe than sorry...