already answered here:
It will depend on many things such as "are these 3rd party products?"
- try to find newest versions (if exists and license allows you to), otherwise try to just re-install them on 2010. You need also to ask
whether you plan to add/update more functionality? - if yes and you
have the option, then you should probably invest in actual migrating
the code to benefit from the new .NET 3.5 features, new improved API,
Many tools existed at the time (WSPBuilder being most used to create
.WSP packages), StSDev or even Visual Studio Extensions for WSS by
Microsoft, make sure you choose an appropriate path to migrate. Visual
Studio 2010 replaces the need for any of those tools now (e.g. support
automatic import from a solution based on VSE for WSS).
You need to assess a little, we only highlight options and
how to migrate web parts with .wsp solution package from sharepoint 2007 to sharepoint 2010