Are there any technical issues on migrating customers and their websites off of reseller accounts and onto a server ?

I am considering starting out as a reseller, then moving up to a dedicated server at a datacenter when requirements come about for it.

(I will be doing Windows 2000 hosting if this makes any difference)

If possible I would like a way to make things as transparent to the end user as possible.

Does anyone have any suggestions (other than something stupid like "use linux") that might bring up any problems that they experienced ?