Query databases on different servers How can I create a query that will find all the databases on different servers?

I have four servers,  PRDSVR, UATSVR, DEVSVR, TRNSVR; with either copies of the same database on each server or standalone databases that may only be on one or two servers.  

I would like to create a query that searches for all databases, listing the server, databases on that server, and the size of each of the databases.  How can I achieve this?

Thanks in advance for any suggestions.
Four part naming convention.

Add a linked server that will define the security context for connecting, then refer to PRDSVR.master.sys.databases and the like.