For documentation, Fedora has a pretty good for basics: http://docs.fedoraproject.org/en-US/index.html
Now regarding your problem I had the same issue and to avoid it I've performed the following as root:
[root@testmachine ~]# xrandr
Screen 0: minimum 64 x 64, current 1600 x 1200, maximum 32000 x 32000
VBOX0 connected 1600x1200+0+0 0mm x 0mm
1600x1200 60.0*+
1440x1050 60.0
1280x960 60.0
1024x768 60.0
800x600 60.0
640x480 60.0
This will provide all the available modes. To add a new one perform the following:
[root@testmachine ~]# cvt 1920 1080
# 1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz
Modeline "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync
Let's create a new mode for XRAND and associate it to the screen.
xrandr --newmode "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync
xrandr --addmode VBOX0 1920x1080_60.00
And now it's time to activate the output
xrandr --output VBOX0 --mode 1920x1080_60.00
the VBOX0 value you get from the first xrandr command to see your display id.
Change the cvt value and update the commands accordingly to match your cvt output.