You have a few options in .net
If you wish to work at page level you can add the follow to your c# code
for a 301 redirect
Response.RedirectPermanent("http://domain.com/newpage");
For a 302 redirect
Response.Redirect(("http://domain.com/newpage");
Or if adding to .aspx page
<% Response.Redirect("http://domain.com/newpage"); %>
If you wish to do it from the web.config file, 1 option is to use the rewrite module
<system.webServer>
<rewrite>
<rewriteMaps>
<rewriteMap name=”Redirects”>
<add key=”/oldpage.aspx” value=”/newpage.aspx” />
<add key=”/oldpage2.aspx” value=”/newpage.aspx” />
</rewriteMap>
</rewriteMaps>
</rewrite>
</system.webServer>
if you start having a lot of redirects you can store these in an external file so
<rewriteMaps>
<rewriteMap name=”Redirects”>
<add key=”/oldpage.aspx” value=”/newpage.aspx” />
<add key=”/oldpage2.aspx” value=”/newpage.aspx” />
</rewriteMap>
</rewriteMaps>
Then add to web.config
<rewriteMaps configSource=”MyRewriteFile.config” />
To be honest I personally do majority of my redirects at page level as there is less room for error.
One word of caution though, you need to make sure you dont redirect a page to a page that is then redirected.
This creates a redirect chain which google wont keep following. By all means do 1 redirect but as you are in charge of your own site you can control the number of redirects, i.e. allwos redirect to the final page.