  We present a sample of 150 narrow-line Seyfert 1s (NLS1s) found within the
Sloan Digital Sky Survey Early Data Release (EDR), only two of which were
previously identified as such. This substantially increases the known number of
NLS1s, and provides a basic method by which to identify many more with
subsequent releases of SDSS data. With its large size and homogeneous,
well-defined selection criteria, this sample will help alleviate two major
problems which have plauged NLS1 research in the past; namely, their relative
rarity and significant differences in selection algorithms between the known
samples. 45 of these SDSS-selected NLS1s are detected at energies of 0.1-2 keV
in the ROSAT All-Sky Survey (RASS), and are found to have ultrasoft X-ray
spectra with photon indices of Gamma >~ 2, in agreement with previous results
for NLS1s. However, about 10-20 of those NLS1s that were not detected by ROSAT
have optical properties very similar to the detected objects, and so should
also have been detected by the RASS. This may be due to either significant
intrinsic absorption in many NLS1s, or a significant sub-class of NLS1s that
have uncharacteristic, intrinsically flatter (hence harder) X-ray spectral
energy distributions.
