Deploying PostgreSQL on virtualized hardware

In a couple months, I'm going to be considering how best to deploy an 
application I have that uses PostgreSQL as its back-end.  It also makes 
heavy use of Perl under mod_perl and UMN MapServer with a sprinkling of 
PostGIS.

I've recently become intrigued by the idea of virtualized servers [0], 
but I don't know anyone who uses them, so I thought I'd ask the list if 
any of you have tried deploying PostgreSQL or any other disk-heavy 
software on them?

I'm not familiar with how the virtualized disks are arranged, how 
volatile the memory is, and so forth.  And, unfortunately, the 
advertising folk don't seem to be very keen on divulging the technical 
details.

It would certainly be nice to pay $60 per month for eight virtualization 
slots and scale up from there as the service grows, rather than buying 
$10,000 worth of servers when they won't be even close to fully utilized 
for a several months.

Any thoughts?

Thanks.

Colin

[0] eg. http://www.gandi.net/hebergement/offre/xen/