[Visual Basic 6.0]
The following function checks out an ArcPress license.
Public Function GetArcPressLicense() As Boolean
  Dim pUid As UID
  Set pUid = New UID
  pUid.Value = "esriOutputExtensions.ArcPressExtension"

  Dim pExtAdmin As IExtensionManagerAdmin
  Set pExtAdmin = New ExtensionManager

  pExtAdmin.AddExtension pUid, 0

  Dim pExtManager As IExtensionManager
  Set pExtManager = pExtAdmin

  Dim pExtConfig As IExtensionConfig
  Set pExtConfig = pExtManager.FindExtension(pUid)

  If (Not pExtConfig.State = esriESUnavailable) Then
    pExtConfig.State = esriESEnabled
    GetArcPressLicense = True
  End If

  If (Not GetArcPressLicense) Then MsgBox "No ArcPress licenses available"
End Function

[Visual Basic .NET, C#, C++]
No example is available for Visual Basic .NET, C#, or C++. To view a Visual Basic 6.0 example, click the Language Filter button in the upper-left corner of the page.