[mtripoli]

http://www.stellarium.org/

[Thomas An.]

Google earth has that. An extremely detailed night sky where you can zoom in on any portion to see Hubble photos and encyclopedic details for most known stars. Quite awesome

[PA3K]

yes, I like stellarium ... I`m using it for few years ... there is a lot of software, but this one I like from the first time

[markps]

Well...

http://www.worldwidetelescope.org/

I guess this is the best one out there.