MobileStarChart is an open source, freeware Astronomy/Planetarium software for Java J2ME capable MIDP 1.0/2.0 mobile devices.
It simulates the whole sky at any point on earth with constellations, stars up to 6 mag, solar systems and some other celestial objects.

You can even search for objects in the sky database like “stars with common name”, “constellation name/abbr”, “planets name, including the Sun and the Moon”, “Messier Objects by its ID number or common name.”

Here are the complete features of this application:

-Both Horizontal and Equatorial Coordinate Display of whole sky.
-88 constellation names, 83 constellation stick figures, 110 messiers and stars up to mag 6.0 (5080 stars, and 50 common star names).
-Full 8 planets plus Sun and Moon is calculated, information is displayed respectively on a seperate screen.
-Location and Date/Time can be set at startup. Applicable for any location on earth given a specific time.
-Sophisticated display control over all information on screen.
-Search for any type of object and GOTO functions.
-Quickly jump over time with adjustable time steps.
-Auto update of celestial object positions.
-Support English and Chinese display of celestial object name
-Tiny 160KB compressed jar file. (for version 0.09)

Download here