  We present the first Spitzer Infrared Spectrograph (IRS; The IRS was a
collaborative venture between Cornell University and Ball Aerospace Corporation
funded by NASA through the Jet Propulsion Laboratory and the Ames Research
Center.) observations of the disks around classical T Tauri stars: spectra in
the 5.2-30 micron range of six stars. The spectra are dominated by emission
features from amorphous silicate dust, and a continuous component from 5 to 8
microns that in most cases comprises an excess above the photosphere throughout
our spectral range. There is considerable variation in the silicate
feature/continuum ratio, which implies variations of inclination, disk flaring,
and stellar mass accretion rate. In most of our stars, structure in the
silicate feature suggests the presence of a crystalline component. In one, CoKu
Tau/4, no excess above the photosphere appears at wavelengths shortward of the
silicate features, similar to 10 Myr old TW Hya, Hen 3-600, and HR 4796A. This
indicates the optically thick inner disk is largely absent. The silicate
emission features with peaks at 9.7 and 18 microns indicate small dust grains
are present. The extremely low 10-20 micron color temperature of the dust
excess, 135 K, indicates these grains are located more than 10 AU from the
star. These features are suggestive of gravitational influence by planets or
close stellar companions and grain growth in the region within 10 AU of the
star, somewhat surprising for a star this young (1 Myr).
