There are several good and recommended vendors of screen protectors for the BlackBerry. These have been mentioned over and over in the threads at BlackBerryForums.com
Dielectric 600-P Smith Chart Impedance Plotter 300-1000 MC Raymond Maine Vintage
$149.99
CU350/PT TA312/PT Field Phone Impedance Matching Network 5915003925981 Military
$39.98
Home grown Antenna Impedance Meter from ham radio estate
$97.50
Antique 1910’s Radio Transformer - National Impedaformer Impedance Matching
$46.00
Western Electric - 440-201 - Telephone Earpiece Receiver. Magnetic Low Impedance
$16.98
ACME Audio Impedance Z-2 Choke (2.66K) 1920's L@@K 3 1/2 X 3 1/4 Inch Working
$22.99
CAHN MC-385-D High to Low Impedance Adapter for HS-33/38 Headsets
$11.86
10 New Nichicon UPW 3.3 uf 50V Radial Capacitors low-impedance
$4.99
Raychem Capacitance - Impedance Calculator 1963 Coxial Cable Conductor Calif
$22.00
Silynx Communications CA0006-00 Intercom High-Impedance Cable Adapter
$89.96