Is NetPrint capable of printing to non-HP printers?

Yes. One of the major advantages of Netprint is the ability to print to a vast number of different model printers (ie Epson, Lexmark, Printronix, etc..) and servers. A destination setting allows you to specify the type of device you are going to be communicating with. LPD (line printer daemon) is often used as a standard to any LPD-capable interface.