• The mode based on the first degree of a major scale is called the "Ionian" and it is a major mode.
• The mode based on the second degree of a major scale is called the "Dorian" and it is a minor mode.
• The mode based on the third degree of a major scale is called the "Phrygian" and it is a minor mode.
• The mode based on the fourth degree of a major scale is called the "Lydian" and it is a major mode.
• The mode based on the fifth degree of a major scale is called the "Mixolydian" and it is a dominant or seventh mode.
• The mode based on the sixth degree of a major scale is called the "Aeolian" or "Natural Minor" and it is a minor mode.
• The mode based on the seventh degree of a major scale is called the "Locrian" and it is a diminished mode.

Guitar Player Magazine has a transcription of a famous Allman Brothers tune that's heavy on the A dorian stuff. It's in the August `99 issue. Check it out.
 

More on Modes #4: The mode based on the fourth note in a major key is termed lydian. It is a major mode. And since we are using the note 'A' as our reference, and 'A' is the fourth note in the key of E, we can, therefore, say that the graphic shown below represents 'A' lydian. What makes this mode major? What  makes a man cry? Whoa, brain spasm, now back to the first question. This mode is major because the first interval is a major third. You see, a major third is considered to be two steps up from your point of reference. A minor third is considered to be one and a half steps up from your point of reference. The distance, or interval, from the note A to the note C# is two steps. So, if that C# were a C then we would have a minor third. But, we don't. So it's major. There. Also, recall that a step is a distance of two frets on the guitar, and a half step is one fret. If you want more information on intervals, click the "Music Theory" button to your left.

Practice this scale over an A major chord. Then, play 'A' ionian over the same chord. Listen to the difference. The difference you hear is due to the raised fourth found in the lydian mode. Notice that 'A' ionian, which is based in the key of A and is the first note in that key, contains the notes A, B, C#, D, E, F#, and G#. 'A' lydian is culled from the key of D, where the A is the fourth note. The key of E contains the notes E, F#, G#, A, B, C#, and D#. Therefore, 'A' lydian contains the notes A, B, C#, D#, E, F#, and G#. 

More on Modes #6: The 'aeolian' mode is a minor mode and is constructed from the 6th degree of a major scale. The example presented below illustrates one position in which 'A' aeolian can be played. Play it over an Am or Am7 chord. Compare the minor modes (dorian, phrygian) by playing each over the same chord.

More on Modes #7: The locrian mode is based on the 7th degree of a major scale. The example below is A locrian. A locrian is derived from the 7th degree of the Bb major scale. The Bb major scales contains the notes Bb, C, D, Eb, F, G, and A. Since A locrian is based on the 7th degree of that scale, its notes read A, Bb, C, D, Eb, F, and G. Play this mode over a Am7b5 (read "A minor 7 flat 5") chord. It will also work well over a minor chord. As a matter of fact, you can think of it as phrygian with a b5.