  The IceCube detector, which is embedded in the glacial ice at the geographic
South Pole, is the first neutrino telescope to comprise a volume of one cubic
kilometer. The search for neutrinos of astrophysical origin is among the
primary goals of IceCube. Point source candidates include Galactic objects such
as supernova remnants (SNRs) as well as extragalactic objects such as Active
Galactic Nuclei (AGN) and Gamma-Ray Bursts (GRBs). Offline and online searches
for transient sources like GRBs and supernovae (SNe) are presented. Triggered
searches use satellite measurements from Fermi, SWIFT and Konus. Complementary
to the triggered offline search, an online neutrino multiplet selection allows
IceCube to trigger a network of optical telescopes, which can then identify a
possible electromagnetic counterpart. This allows to probe for mildly
relativistic jets in SNe and hence to reveal the connection between GRBs, SNe
and relativistic jets. Results from IceCube's triggered GRB search and a first
limit on relativistic jets in SNe from the optical follow-up program are
presented.
