A few days ago, I've published a link to a series of OSPF-over-WAN tutorials by Arden Packeer. He went a step further and analyzed what happens if you mix supposedly incompatible OSPF network types in the same IP subnet.
The various models you can use to run OSPF over partially-meshed WAN (usually Frame Relay) are complex enough to make you scream ... or switch to EIGRP :) Arden Packeer did an excellent job in his three-part tutorial describing broadcast and non-broadcast network types, point-to-multipoint network type and point-to-point links over Frame Relay.
If you still have problems with OSPF after reading all three tutorials, use point-to-point subinterfaces.
Routing protocol redistribution is one of those tough Cisco IOS topics that everyone struggles with sooner or later. To ease your path to mastering the redistribution issues, Petr Lapuhkov wrote two articles: the theory of route redistribution and a simple case study.
