Rough guide to Brazilian political parties

There are 27 political parties registered for the elections in Brazil next Sunday. Their names can be placed in the political spectrum, roughly from left to right, as follows:

5 communist parties: PCdoB, PSTU, PCB, PCO, PSOL;
6 labor parties: PTB*, PDT*, PT*, PTdoB, PRTB, PTN;
2 socialist parties: PSB, PPS;
1 social democratic party: PSDB*;
1 green party: PV;
6 generic label parties (democratic, progressive, or republican): PMDB*, DEM*, PRP, PP, PRB, PR;
3 christian parties: PTC, PSC, PSDC;
3 others: PMN, PHS, PSL.

Notes and disclaimers:
- The ideological affiliations of the communists are as follows: PCdoB - Maoist-Stalinist (Albanian line); PSTU - Leninist; PCB - Soviet Brezhnevite (refounded); PCO - Trotskyite; PSOL - Cuban Line (in transition to Chávez-led).
-Each of the left wing parties would probably reject the credentials of the others as properly communist, or socialist, or laborite. Nor would they agree on who is a dissidence of whom.
-Additionally PPS is the former Communist Party (anti-Stalinist), now undistinguishable from fellow eurostyle social-democrat PSDB.
-There are no explicitly conservative parties, although DEM and PP come closest. However there is a smattering of right-wingnuts or extreme nationalists in most if not all of them. There are no open liberals (in the European sense) in Brazilian politics.
-The christian parties all have additional specs such as social or labor but to the best of my knowledge tend to be neither.
-Each of the six parties marked with a star* usually controls 5% or more of the seats in at least one chamber of congress, and are therefore more costly for wholesale purchase, although the fact that neither PDT, nor PTB, nor PMDB have any identifiable ideology makes them affordable at retail.
-The smaller parties are more malleable and can be persuaded to support pretty much any campaign. The exceptions are the communist parties, populated by students and public employees, thus directly funded by the taxpayers.

For more information, consult the electoral tribunal's site.