Transit permissions through Eastern Europe

With the introduction of some of the eastern European countries(check
internet for details) to the European union in 2004 , it is now
possible to transit these countries without a visitor visa & with a
Deutsch residence permit (Residence permit issued by any of the Schengian countries).
I successfully completed the trip Munich - Prague - Krakow(Poland) - Slovakia - Budapest (Hungary) -Vienna ---Munich.
I did not face any problems during this travel but there are a few conditons which need to be followed as per the 'Transit Visa
Guidelines'

1: The entry & exit has to be a different country. E.g. If you are
entering Poland from Chz Republic the exit has to be a different
country e.g. Slovakia. If you turn back from Poland to Chz Republic I
am afraid questions can be asked & might be troublesome, not at all
advisable.

2: The maximum of 5 days is allowed during the transit per country.

3: It is strongly advised to have pre booked railway tickets of
forward journey from Deutsche Bahn or by Air.
Also advised is confirmed hostel/hotel reservation or email
confirmation & medical insurance. I was not asked any of these but it
can be asked since you will be on transit. Also keep a photo identity
other than you passport like pan card, company id etc. I was asked for
a proof during entry to Poland.

Poland & Hungary is very beatiful and I would suggest to visit these
countries with this opportunity.

depends, I went to Estonia a few years ago, and needed a Visa, didn't matter that I lived in Germany. The place of residency is not always the issue its the passport that the traveller holds. Always best to check ahead of time, as every country has different rules.
At one time Canadians could travel to Estonian, Lithuania and Latvia with only needed visas for 2 of the countries, and the other country would accept that if you had a visa for 2 of them you were covered to enter their country... was a weird rule, but no longer in effect.
Some countries like Czech Rep have transit visas, but not all countries do.