Well, you have to know (if you don't) that the German chancellor isn't elected directly. The parliament elects him. German people can only vote for a party.
The new German Bundestag will have 598 members (or maybe a few more, but that's quite complicated). To get into it, your party needs at least 5 % of all votes (there's another possibility, but that's quite complicated too
). There are only 5 parties who have got a chance to get in:
SPD - social-democratic party. Schröder is in it. It's rather left (but not much).
CDU - christian-democratic party. Stoiber is in it. Rather conservative (but not much either, in fact both are quite similar).
FDP - liberal party. They have candidate for chancellor as well (Guido Westerwelle), but that's more a joke.
Bündnis '90/Grüne - the Green Party. Currently governing with the SPD. Foreign minister Joschka Fischer is a member of it.
PDS - party of the democratic socialism. Origin was the KPD of East-Germany, and it's still mostly based in the east part of Germany.
To govern, you need more than 50 % of the places in the Bundestag. If one party doesn't reach that (and it won't happen), there has to be a coalition.
SPD and Green party want to continue. CDU wants FDP. FDP would take SPD or CDU. No one wants the PDS.
Right now it seems the SPD will win. But probably all depends on the PDS. If they get in, maybe none of the combination above will reach 50 %.
Solution: maybe big coalition (SPD/CDU, rather unlikely), 'Ampel'-coalition ('Ampel' means traffic-lights = SPD/Green/FDP = red/green/yellow).
Will be close.