R – Are there any mocking libraries that support the .NET Compact Framework

You've not given us much detail, like the device you're using or the printer type you want to print to (local, lan, serial, network, etc), however I'll see if I can at least point you in the right direction.

The de-facto standard for CF printing is PrinterCE from Field Software. PrintBoy from Bachmann Software also works well. I'm not certain if eitehr has the ability to print barcodes though.

Now if you're printing barcodes, that suggests that you're using a device like a Symbol (now Motorola) or Intermec handheld. If that is the case then those manufacturers have their own SDKs that allow printing.

If you are printing to something like a Zebra barcode printer, they typically have some serial PCL commands for printing barcodes as well, so you don't actually need to "print" the barcode. Instead you send the PCL command to tell the printer that the data should be output a barcode instead of text. The printer manufacturer can provide a PCL reference, as the PCL for these types of things isn't standardized.

OCR is a tricky beast, which is why you probably won't find many free, high-quality, OCR engines. The OCR app on your phone (I'm guessing it's an HTC phone with WorldCard Mobile?) probably has an extremely-well-protected OCR engine or it farms out the work via a webservice.