Hello Kai,
I went through the previous posts pertaining to the signal grounding issues .
They were very much informative.
I would like to discuss with some of the information i got in my search.
Let me consider i am doing a two layer PCB design.

Can i follow points mentioned below.

1)Manual routing
2)the signal and ground traces are routed on the top side.
3)the bottom layer could be made a solid ground plane with the GND pins of the components connected to it.

In case of mixed signal design then:

1)manual routing on top layer.
2)The analog signals should be routed seperately from that of digital signals.
3)The AGND nets should be connected to the analog ground plane in the bottom layer
4)The DGND nets should be connected to the digital ground plane in the same bottom layer(i mean splitted ground planes in the bottom layer).

These two planes should be connected at a point known as star point using a ferrite bead or an RLC circuit.

Did i got it right.

and one more thing,
I have taken that 'the ground planes are nothing but the copper pour's. Is that correct?

suggestions needed.

-suresh.