This chapter deals with a description of a nanoparticle plasmon waveguide of a different flavour, combining plasmonic excitations with photonic-crystal-based paradigms. The curved surface of the particle excerts an effective restoring force on the driven electrons, so that resonances can arise, leading to field amplification both inside and in the near-field zone outside the particle. For particles of sub-wavelength size, the localized plasmon resonance has the character of a dipole. In the case of gold and silver nanoparticles embedded in a low-permittivity dielectric, the dipolar resonance falls into the visible region of the electromagnetic spectrum. Metal nanoparticle waveguides therefore remain an exciting field of study, almost a decade after their initial description. In the context of coupling between metallic nanoparticles for applications in waveguiding, it is useful to briefly review the basics of the electromagnetic fields associated with an oscillating electric dipole.