"Unknown Publisher" - Anything outside of the trusted zone won't be able to install without a certificate
Providers of certificates
www.verisign.com - $400 for one year org certificate
VeriSign?Create Code Signing Standard Digital ID - In conjuction with Microsoft Authenticode Technology, this enables you to digitally sign 32-bit exe (PE files), .cab, .dll and .ocx files.
Information needed:
Step 1. Enter your Technical Contact information.
Step 2. Enter your certificate information.
Step 3. Verify your Certificate information and enter a challenge phrase for this certificate
Step 4. Enter your Organizational Contact information.
Step 5. Enter your payment information.
Step 6. Confirm and submit your order.
Step 7. Print your order confirmation and review the VeriSign?Create authentication process.
Fully Validated - $50,000 Warranty - Full Support for Microsoft Authenticode technology - Digitally sign 32-bit .exe (PE files), .cab, .dll and .ocx, files - 30 day Refund and Reissue Policy - Telephone email and web support - Express delivery - Starting at only $99 per Certificate per annum
www.ascertia.com - Free Digital Certificates
Registration Code Generators
http://tangentsoft.net/port/ - Registration key code generator for Palm OS. Nice discussion of the issues involved in generating Palm keycodes, length / security tradeoffs, etc.
Assemblies are compressed, encrypted, and then merged into a Win32 application; decompilation and disassembly tools like ILDASM can't load a native executable.