If there once was life on Venus, it was so long ago that we might never know about it. If we do eventually drop rovers or some other probes on Venus again, it won't be for quite a long time. Mars is somewhat temperate compared to Venus, so the rovers that landed in January are still working. Anything we sent to Venus with present technology would stop working in a very short amount of time, so it just isn't worth bothering with at this time.
I don't think that's correct, there is no probe currently orbiting Jupiter that I know of. Cassini went by Jupiter a couple years ago, and is now exploring Saturn. Its functioning well as far as I know and will drop Huygens, a probe, onto Titan in January 2005.