The "Elo formula" Generally:

Rnew = Result old + C1 * (W - E)

W = The percentage points of the result of the match (e.g.: 100% = won, 50% = undecided, 0% = lost)
Rold = Old Ranking (Elo points)
Rnew = New Ranking
E = Expected percentage points (calculated beforehand)
C1 = Constant one (at present: 50)

The prediction of percentage points are calculated as shown below:

E = 1 / (1+10^ (-(R-Rother)/C2))

R = Ranking of the own team
Rother = Ranking of the opponent
C2 = Constant one (at present: 400)

The same calculation is then accomplished once more from the view of the other player, in order to compute his/her new score.

Example:
Match result: 3:6
Persentages: 33%:66%
old Elo points: 1000:1000
new Elo points: 992 (-8) : 1008 (+8)

Expectation of profit:
E = 1/(1+10^(-(1000-1000)/400)) = 0.5
new points for team1: Rnew = 1000 + 50 * (0,33 - 0,5) = 1000 - 8 = 992 (rounded)
new points for team2: Rnew = 1000 + 50 * (0,66 - 0,5) = 1000 + 8 = 1008 (rounded)