Agreed that the more we know about how life began on our much-newer planet the more we'll know about how it might start elsewhere. For instance, the best theory I've come across so far involves undersea alkaline hydrothermic vents, particularly under archaic conditions (acidic ocean, no O2). Some of the structures that come out of simple mineral deposition look a bit like cells. The walls are a good bit thicker, but there's a large PH difference across them - and all life as we know it is powered by a proton difference across membranes.

The leap from prokayote to eucaryote (and so eventual multicellularity just given the change in the membrane area to volume that comes out of having mitochondrial christae) seem much less likely.

Then of course comes the issue of recognizing the products of life from astronomical (literally) distances. The best theory I've seen around that has to do with how many copies of something detectable (e.g. changes in a star's spectra as it passes through a planetary atmosphere) and how many 'steps' might be required to produce that. The advantage to that theory is that it doesn't limit 'life' to carbon-based but instead recognizes products of processes complicated enough and numerous enough that it could be life - without getting into the whole 'what is life?' debate.

It's an interesting area indeed...