3 teams....2 Spots

The 08/09 European season will be the last season in which 3 Portuguese teams will have a chance to compete in the Champions League. As it stands right now, the top 2 teams get automatic berths, while the 3rd place finisher will be drawn into a qualifying round.
Portugal's European coefficient has gone considerably down, all because of poor displays by Portuguese clubs, as a result, UEFA's coefficient point system has punished the Portuguese Bwin with the loss of an automatic berth.
For the 09/10 Champions league edition, only 2 spots will be available, the champion will get an automatic berth, while the runner up will be playing in the qualifying round. With that in mind, this year's berths take on special importance.

With Porto having wrapped the league title about 4 months ago, it is up to the following 3 to fight for the remaining 2 spots.

Sporting is in second place with 49 points, Guimaraes also has 49 points, but at a disadvantage due to the head to head tie breaker with Sporting(and Benfica), Benfica see themselves on the outside looking in, as they are in 4th place with 48 points. Two games remain to settle who will get the final 2 spots. For Benfica it'll be the only thing that can dampen the disaster that this season was, possibly the worst in many years.
For Sporting, a Champions League berth would also be the attainment of one of their secondary goals, as well as their third straight year with direct entry to the group stages.
For Guimaraes it is the corollary of a consistent season, which sees them where they are today, much because of Benfica's and Sporting's inconsistencies all year. Surely the Champion's League was a distant thought in the mind of Cajuda's men in the beginning of the season, after all, they had just been promoted, but as the season went on, what went from a distant thought became a big possibility.

Here's what the three will have to deal with in the last 2 games.

Sporting

With Liedson being declared out for the next two games, due to a twisted knee, Sporting will need to find offensive solutions to win 2 very tough matches.
This weekend they will make the trip to the very tough Mata Real building, the home of P. Ferreira. P Ferreira is fighting relegation, and they will play their lives in the next 2 matches. Playing at smaller Mata Real has always been a very difficult task for any team, the proof is in the numbers, as P Ferreira has only lost 4 times, this year at home.
The following week, Sporting has a chance to finish strong at home against Boavista. Boavista has struggled away all season, having only won once away from Bessa, nonetheless the clashes between the two are always very competitive.

Guimaraes

For Guimaraes, 3rd place might put them in a very delicate position. Yes they will be in, but playing in the qualification round, would see them encounter a tough team being that their European team coefficient is very low. If they get past that, or they qualify from second place, that same coefficient would see them being drawn out of pot 4(4th seeded), which would also see them encounter very tough 1 and 2 seeds. However, in the group stage, Guimaraes will have the opportunity to generate significant revenue, with 3 home games.
Guimaraes will face Belenenses this week, who despite just being handed out a 6 point deduction(Meyong case)will still be fighting to get into the Uefa Cup. A tough game away for Guimaraes.
The following week Guimaraes will host Estrela da Amadora. Guimaraes should have no problem beating Estrela, not to mention their supporters will be in force, as they have been all season. The last game of the season and the possibility of playing in the Champions League will only serve to create an even more favorable home atmosphere for Guimaraes.

Benfica

Benfica will try to finish the season with two wins, and hope the two above them slip. The two wins would see Benfica end the year on the right foot, and on a high note. Rui Costa deserves it, and the Benfiquistas who have stuck with the team all year deserve it also. Ascending on the table and achieve a Champions League birth, could possibly be the only thing that will make Benfiquistas forget some of the disaster this season has been.
Benfica will play Estrela da Amadora this week. Tough away game, against a team who is fighting relegation. The final game of the season, and Rui Costa's very last game with a Benfica Jersey on, will be against Vitoria de Setubal. Definitely the tougher of the two remaining games, but being Rui Costa's last game, we can expect a special Benfica, playing a game worthy of a dignified send off, one worthy of only the predestined, and of few players Benfiquistas have ever seen gracing Estadio da Luz, new and old.

All three teams will finish at home, and all have, i would say, at least one very tough game. This weekend will clearly be one weekend which will set the stage for who will be where, come the final whistle two weekends from now.