Strong guiding provided by the high-delta microstructured fibers allows for efficient intermodally phase-matched harmonic generation with femtosecond pumping at telecom wavelengths. Visible harmonics are generated in a number of distinct transverse modes of the structure. We present a detailed experimental and theoretical study of the third harmonic generation in such fibers including phase-matching wavelengths, far-field intensity distributions and polarization dependence. Good agreement between the theory and experiment is achieved.