A simple, but imperfect way of doing is as follows.

Use IPAC's program, Montage, to mosaic your own images or use the online tool to mosaic data from 2MASS, SDSS, etc.

You can then combine these mosaics in (say) the J, H, an K-bands using ds9.

% ds9 -rgb -red 2MASS_K.fits -green 2MASS_H.fits -blue 2MASS_J.fits &

This will open the three images in an RGB frame. You will be able to set the scale of each image until you can create a pleasing balance and bring out the intereting features.