How to convert an .stp file to a .wsp file
1. In Windows SharePoint Services 3.0, create a site that is based on the template, and then upgrade the site to SharePoint Foundation 2010.
2. In SharePoint Foundation 2010, on the Site Actions menu in the upgraded site, click Site Settings.
3. On the Site Settings page, under Site Actions, click Save site as template.
4. On the Save as Template page, enter a File name and Template name, and then click OK.
The site template is saved as a .wsp file to the Solutions Gallery for that site collection and you can create new sites that are based on that solution.
Or Try this...........
How to convert an .stp file to a .wsp file
Using .stp file create a site MOSS 2007.
Backup the database for that site and restore it on SharePoint 2010 Environment
Save this Site as Template in SharePoint 2010
Now we will get .wsp file
Backup the database for that site and restore it on SharePoint 2010 Environment
Save this Site as Template in SharePoint 2010
Now we will get .wsp file
Now we can move this wsp file to any sharepoint 2010 Environment..
