DNSHow to  redirect web traffic but not email

Hi
I have a customers site where his site and email and other services such as forums are resident - all on shared ISP hosting.

I am building a replacement website on a different hosting location ( same domain name) under a sub directory called site.
I don't want to disturb ( or reconfigure ) his email service and hence many email clients.
I wish to redirect his web traffic to the new website.
How do I do this ?

I am unclear about benefits of using DNS at registrar vs (different) hosting location.
In above case we are configuring source DNS - in other cases where there is a choice are there befefits in using one over the other ?

THX

K

Solution: DNSHow to  redirect web traffic but not email

The replacement website (ie- www.test.com/site) will point to the new hosting location (ip address) and it may take from 24- 48 hours to propagate across the internet.