When I become a reseller, what do I need to know and have if I decide to switch providers and have to move my clients web sites? just dns1.mydomain.com, or more?

Apart from DNS changes you will have to move your sites onto your new webspace at your new provider.

Most hosts will do this for you either free or for a charge.

So the transferring process can be hindered if the first provider has bad business practices, even if I have the dns in my domain name?

Originally posted by Dan Sternberg
So the transferring process can be hindered if the first provider has bad business practices, even if I have the dns in my domain name? Only if the first provider shuts you down without cause.

It is your responsibility to do backups for "your" clients...at least weekly. Most webhosts that offer reseller packages create daily or weekly backups...but you still need to download them locally!

Right now cPanel/WHM is the most common control panel and if you later transfer to a different host that also offers cPanel, it's very easy to restore the backups you have. It will restore email, html, SQL, subdomains, ect.. Most times they will do this for you for free (to a limit).

As for the nameservers (ns1 & ns2), all you need to do is change the IP address to the ones given to you from your new host (in the welcome email).

Have a look here:
Changing Web Hosts? Step-By-Step Guide (http://www.webhostingtalk.com/showthread.php?s=&threadid=312983)

Thanks for the tips and links. Probably not as big a deal as one might be led to believe.