Install XCode on Lion fresh install
Correct. Xcode is only available via the App Store to non developers here. Registering an Apple ID is free and any email address can be used. 

Alternatively, if you are a registered developer you can download the DMG from the Developer site here* 

X11 is still a standard part of the Lion installation.

Also, note when registering an Apple ID for the App Store you are not required to provide credit card details as seen below. The option for none is available.



* Developer Account Required