Key Signatures


C Major= C, D, E, F, G, A, B, C

G major= G, A, B, C, D, E, F#, G

D major= D, E, F#, G, A, B, C#, D

A major= A, B, C#, D, E, F#, G#, A

E Major= E, F#, G#, A, B, C#, D#, E

B Major= B, C#, D#, E, F#, G#, A#, B



those should be the only ones you need right now, playing rock guitar.
here's a formula that might help you with the keys and their modes.


I=	  Ionian/major scale
ii=   Dorian mode
iii=  Phrygian mode
IV=	  Lydian mode
V=	  Mixolydian mode
vi=	  Aeolian mode
vii=  Locrian


now, place it like this to get the kneck in a key:
Key of C
I= 	 C
ii=	 D
iii= E
IV=	 F
V=	 G
vi=	 A
vii= B


Key of G
I=	 G
ii=	 A
iii= B
IV=	 C
V=	 D
vi=	 E
vii= F#