Tethered capture is a fantastic tool, it can really speed up your workflow, and for some types of shooting it will allow your client to view as you shoot. In Lightroom3, just go to the "File" menu and choose "Tethered Capture" to set it up, then as you shoot it will bring the images over to your computer and apply presets and tag. Below is a list of currently supported cameras.
Canon • EOS 5D • EOS 5D Mark II • EOS 1D Mark II • EOS 1Ds Mark II • EOS 1D Mark III • EOS 1Ds Mark III • EOS 1D Mark IV • EOS 7D • EOS 500D (Rebel T1I(EOS /Kiss X3 Digital) • EOS 450D (Rebel XSI/EOS Kiss X2) • EOS 1000D (Rebel XS/EOS Kiss F) • EOS 350D (Rebel XT/EOS Kiss Digital N) • EOS 400D (Rebel XTi/EOS Kiss Digital X) • EOS 20D • EOS 30D • EOS 40D • EOS 50DNikon • D3 • D3s • D3x • D90 • D200 • D300 • D300s • D700 • D5000Leica S2 (Lightroom 3.2). Not supported on Windows XP.