The first image has a generic low contrast approach beginning with very soft lighting (overcast conditions) plus possible further adjustments (contrast reduction / mild soft focus effects). The colours have then undergone local modifications, the top part of the image has been tinted pink and the bottom tinted green this can be done most easily with adjustment layers and gradient masks.
The second image has either been through Photomatix or some other "HDR" processing, either from one exposure or many, or has had extensive use of fill light and the clarity slider in Lightroom. On top of that some colour adjustment has taken place, looks like split toning (or cross processing) whereby the highlights are tinted one way and the shadows another.
The bottom image has mixed lighting to begin with, possibly a bounced flash in addition to available light. Looks like a flash behind the subject also. Vignetting has been added in post as well as extensive skin smoothing.