Near-field Raman spectroscopy with high spatial resolution is used to study single-walled carbon nanotubes (SWNTs) within dense samples. A sharp, laser-irradiated metal tip acts as a near-field excitation source causing an enhanced Raman signal within close proximity of the tip. We present optical images of different Raman modes with a spatial resolution better than 15 nm. Local spectroscopy allows us to identify and distinguish tubes with different structures on the nanometer-scale and to observe variations within the spectrum of individual tubes.