Hi guys,
I currently have a reseller hosting account without root access.
In about 4-5 weeks I am renting a dedicated server with root access.
The reseller account runs on linux, and uses cPanel and WHM.
The servers runs on Linux, and will be using Plesk (my preference).

Is it possible to transfer my reseller hosting accounts to the server ? How would this be done? Does anybody here have the experience to do this? And how much?

Thanks

P.S. I know I would need to chaneg the name server settings of the domains though.

Yes, this is easy

Plesk has an account transfer script. You just need root access to the server you are transfering TO. (Which you do)

Thanks mate.

Is this also the same for a Windows reseller account to windows dedicated server?

And also, from a linux reseller account (cPanel) to a windows dedicated server with Plesk.

It may not be possible to transfer the accounts using an automated script. This depends on the connection between the two hosts and if the account(s) is big it is possible for the connection to time out.
Try and if there are any problems use the old fashioned way :

1. Download the web-content via FTP to your PC
2. Upload it to the new host

If you have SSH access to your accounts with the old host, zip (or tar) the web-content and again download it to your PC and upload & unzup (untar) to your new server.

Have in mind that e-mails may not imporat correctly or at all.
In case you are not sure and do not wish to risk, download them via IMAP.