Standalone Barcode Reader that checks against file
The Motorola 2090 comes with a couple of basic inventory applications that are close. The source for them is provided as part of their VS2008 SDK, and rolling your own with more specific requirements using VB.NET, C# or whatever, is pretty straightforward.

All of the handhelds we've used over the past 10+ years had SDKs available that provided everything from basic access to on-board scanners and radios right up to full blown IDEs and dev environments. If you can handle VB, then you can write code for any handheld.