Yes, you can use Quick License Manager with Delphi.
You need to create COM Wrappers for the IsLicense50.dll or QlmLicenseLib.dll using the TLIBIMP utility located in the Delphi bin folder.
Then, you need to register the DLLs as follows:
regasm /tbl "C:\Program Files\Soraco\QuickLicenseMgr\QlmLicenseLib.dll"
regasm /codebase "C:\Program Files\Soraco\QuickLicenseMgr\QlmLicenseLib.dll"
The first command will generate a file called QlmLicenseLib.tlb. You need to add a reference to QlmLicenseLib.tlb in your development environment.
The second command registers the DLL as a COM object. When you distribute your application, you need to execute this command again on the end user system.