i've seem people mention that slony can be used to migrate between 
releases, and i want to start looking at a migation plan from 7.4 to 7.5 
so that we don't have downtime during our upgrade.

I haven't been able to find out how to do this yet.  Will this be a 
pretty straight forward process, or are there going to be lots and lots 
of mantual steps involved.

can someone point me to a howto, or similiar documentation that explains 
this process?

thanks

--brian