We have found one software suitable in our database for this conversion.
It might be possible to export contacts from Microsoft Windows Address Books (.wab) to a iCalendar calendar file (.ics) with some good e-mail and contact management software like Outlook.
Sometimes, you need to use a CSV file type as a intermediate step between those two file type, so you have to first export wab to csv and then import that .csv file to produce .ics file.
WAB
Files with wab file extension may be found as contact archives in Microsoft Windows Address Book format that was used in Outlook Express, a now discontinued email client.
ICS
Files with ics extension are calendar data in exchange format which is widely accepted in many personal information managers and e-mail clients such as Microsoft Outlook, or Apple iCal. It is an universal format for transporting calendar data and events from one program to another.