Redirect Old MOSS 2007 to sp2010

How to redirect Old MOSS 2007 ( IIS6.0 ) Site to New SharePoint 2010 Site in Migration:

Requirement is, 

We have migrated contents from MOSS 2007 (IIS6.0) to SharePoint 2010 and gradually moved site collections one by one It took a while to address migration fixes and make them in a good shape for some  site collection.

Meanwhile, We had to redirect Users to migrated SharePoint 2010 site collections when they hit old MOSS 2007 site collection URLs or access them from bookmarks. Ideally, once migration is completed, we must place a server redirect in publishing server to send users from old URL to new URL.

But in our case, As we move site collections one by one, only few site collections needs to be redirected.

Redirection URL scope would be varied  from site level or site collection level or list & document library level.

The solution, we need to below options,

1. Create custom httpmodule to redirect httprequest and make entries to web.config.
2. Third Party tool  ( ISAPI rewrite URL ) available at free of cost from codeplex. URL mapping using regex ( regular expression validator rule )  available. for more details, refer http://rdacollaboration.codeplex.com/
3. If Source site is IIS7.0, refer this at free of cost http://www.iis.net/downloads/microsoft/url-rewrite