Energetic outflows, often colliinated into two oppositely directed jets, are frequently found to be associated with new-born stars still buried in their parent molecular clouds. Millimeter wavelength
observations of molecular transitions of species such as CO have shown that the cold molecular component of the outflows has velocities up to 60 km.s^-1 with a total mass ranging between 0.01 Mq for low mass stellar sources to over 100 Mq for flows having several massive stars at their core. Optical and near infrared
observations reveal a hot (over 10^3 Kelvin) flow component exhibiting velocities in excess of 300 km s^-1. Although some jets associated with low luminosity sources, such as HH-34, exhibit a very high degree of colliination, the structure of most massive outflows is complicated, appearing "bipolar" only in low angular
resolution observations. At high resolution, many sources exhibit lumps, oscillations, or flow in more than just two directions. In this talk I will review millimeter-wave as well as some near-infrared and optical observations of this impotant phase of stellar birth.