I had a friend who told his wife to cremate his body and take his ashes out into the Texas Gulf Bay and spread them in the water. His wife did exactly what he asked. Yes, it's illegal BUT>>>>if no one knows then it's OK!!
we went through this with my father in law a few months ago
the crematorium told us that is we wanted to dispose of the ashes in a public place we had to get permission from the local authorities
as for me personally, I always liked the idea of being donated to science...I always wanted to go to college ;)
but
the more I think of it, the more I think it is better testimony for Christians to be buried
there are several verses that speak of death as "sleep" and the new testament continues the idea of the resurrection of the dead as taught in the old testament
personally I don't think it makes much of a difference, God created us from the dirt, I'm sure He can resurrect us from the ashes