Watch the The V-IV or I-bVII online guitar lesson by Ravi from Guitar Lab: 30 Rock & Pop Progressions
Two major chords a whole step apart are almost always called the V and IV in strict classical theory. However, because of the way they are often implemented with the V chord sounding and functioning as the root of the key, we frequently refer to the relationship as the I-bVII. Either way, the end result is the same. Practice with 6th string barre chords and 5th string barre chords, as well as open strings.
Examples: Soul Man, Cocaine, Tequila, You Really Got Me, On Broadway