problem with domain DNS

[HAVE1.COM]

Greetings,

I have a domain that I just transferred to OpenSRS from NetSol - everything
transferred ok. I then went into the manage option for the domain and
changed the Name Server to a different server. This was done on Friday
(April 20). The whois on OpenSRS acknowledges the changed name server, but
back on Net Sol's whois the old name server is still listed... is there some
sort of holdup somewhere? How long does it usually take to change the name
server?

Thanks

GABE NOWAK