Is it possible to communicate between two networks with different routing protocols (lets say one with eigrp & other with ospf). How??

Yes  Redistribution of EIGRP into OSPF solves such  Issue

YES IT IS POSSIBLE TO COMMUNICATE BETWEEN TWO NETWORK WITH DIFFIRENT PROTOCL BY REDISTRIBUTION IN NETWORK.

you can achieve this by OSPF, EIGRP redistributions, either one way or2 way redistributions

some points to be taken into consideration while redistribution like

seed metric

if selectice route redistribution is needed from one routing protocol to another

Yes it's possible by using redistribution

Yes by redistributing OSPF into EIGRP and Vice Versa

Yes we can use redistribution option to run different network as well as routing protocol.

It's possible to achieve two way communication between two routing protocols with redistribution, OSPF can be redistributed into EIGRP and visa-versa. 

Yes, 2 different routers or two or more networks can communicate to each other through re-distribution.

Sure it is possible, by using redistribution. 

any routing protocol can redistribute its entries to another routing protocol

Yes, Redistribution is answer. We can use multiple routing protocols in our network and redistribution will help us to to exchange routes .

Yes!! this is possible that two network can communicate with two different protocol. All we need to is redistribute each protocol routes.