Champions League

The Champions League contains 32 teams in the group stage, and is be preceded by three qualifying stages. The champions of all countries enter the Champions League, but high ranked countries can send up to 4 teams. Some teams of high ranked countries are directly qualified for the group stage, while others have to play qualifying rounds. See wikipedia for more general info.

CHAMPIONS LEAGUE
1st Qualifying Round	July	30 champions from countries ranked 23 or lower
2nd Qualifying Round	Jul-Aug	involving 28 teams: 15 winners from 1st qualifying round 7 champions from countries ranked 16-22 6 second-placed teams from countries ranked 10-15
3rd Qualifying Round	August	involving 32 teams: 14 winners from 2nd qualifying round 6 champions from countries ranked 10-15 3 second-placed teams from countries ranked 7-9 6 third-placed teams from countries ranked 1-6 3 fourth-placed teams from countries ranked 1-3
Group Stage	Sep-Dec	involving 8 groups of 4 teams each: 16 winners from 3rd qualifying round 9 champions from countries ranked 1-9 6 second-placed teams from countries ranked 1-6 1 defending cup holder
Play-offs	Feb-May	involving 16 teams: 8 group second-placed teams and 8 winners from group stage play the 2nd round, the quarter finals, the semi finals, and the final

Losing teams in the 3rd qualifying round enter the 1st round of the UEFA Cup, and third-placed teams from the group stage enter the 3rd round of the UEFA Cup.

The defending Champions league cup-holder always takes part. If the defending cup-holder does not finish in a qualifying place in their domestic competition they will come in at the expense of the last-placed side of that association, except for associations ranked 16 or below (which implies that the champion of each country always takes part). In this case the last-placed team for the Champions League of that association has to take part in the UEFA Cup. Only if the defending Champions league cup-holder also did not qualify for the UEFA Cup this will lead to an additional UEFA Cup berth for that association.

If the defending cup holder already qualified directly for the group stage of the Champions League, the champion of the 10th country on the country ranking list will gain direct access to the group stage, the champion of the 16th country on the country ranking list will gain direct access to the 3rd qualifying round, and the champions of the 23th and 24th country on the country ranking list will gain direct access to the 2nd qualifying round. Similar changes are made if the cup holder already qualified directly for one of the qualification rounds.

If in the group stage of the Champions League two or more teams finish equal on points after all the group matches have been played, the following criteria are applied to determine the group rankings:

1. Higher number of points obtained in the matches between the teams in question
2. Superior goal difference from the matches between the teams in question
3. Higher number of goals scored away from home in the matches between the teams in question
4. Superior goal difference from all group matches played
5. Higher number of goals scored
6. Coefficient points accumulated by the club in question, as well as its association, over the previous five seasons (Team Ranking)

See the Regulations of the UEFA Champions League 2007/2008 (pdf file of 480 kB at uefa.com) for a complete and formal description of all regulations.

Source : http://www.xs4all.nl/~kassiesa/bert/uefa/