Sometimes it's nice to get a jazzier sound when soloing on rock/pop tunes. Especially now that a lot of hip-hop/dance grooves are so jazz oriented, a simple understanding of jazz is useful.

Most of the time, guitarists build rock solos around the "Blues scale" (a.k.a. pentatonic), or around one minor or major scale, using that one scale over the whole tune. Jazzers, on the other hand, tend to play on each chord in a song. Just like most rock players have licks built around the blues scale, jazzers have licks built around the arpeggios of 7th chords. These arpeggios usually emphasize the 9th, 11th, and 13th of the 7th chord.

For example, lets say we're going to jam over a Gm7 chord:

most rock oriented players would play on a Gm " Blues Scale";:

or a Gm Scale

A jazzer might play licks built on a Gm9 arpeggio:
or a Gm13 arpeggio:
Instead of thinking about a scale, fill in the arpeggio, or add the notes above each note in the arpeggio. Feel free to experiment, just so long as you come back to - resolve to- the notes in the arpeggio you can't hit any sour notes...
Any chord can become "jazzy" if you use an arpeggio over it. To build your arpeggio, simply find a chord, then play the 1st, 3rd, 5th, 7th, and 9th (and 11th and 13th if you're adventurous) of that chord, from low to high. Always visualize a chord form under each arpeggio and just have fun with the notes in between the notes in your arpeggio. Here are some arpeggios along with their parent chords to help you get started (on most of these play 1 3 5 7 9 then double back to 1 and play 1 3 5 7 9 in the higher octave.):

Don't feel that if you use these arpeggios you can't use the blues scale too. This stuff doesn't replace anything - add this material to what you already know - use it all. Try using the blues scale and then throw in a jazzy arpeggio, then go back to the blues scale. Anyway, here are a few typical jazz licks that will fit right over the arpeggios given above. Feel free to change them and make them you own. Trust your ears and your instincts - if it sounds good to you then it probably is...