Registrars will keep the domain for at least 60 days after expiration. I have seen netsol keep domains for over 2 years. Once it is ready to be deleted you will see a notice in the whois that says the name points back to the local database, like its an error. That means the name is in purge. Then you wait for about six days while it is in purge. Once thats over you can register it.
If you see a domain that has been expired for over 90 days on netsol you can call them and have them delete it. I did that and it took 2 weeks from my call to when it was dropped.
Korkus pretty much gave it to you, if it's registered to NetSol / VeriSign former Network solutions, i got a domain 9 months after it expired, my tip is to call them about once a week, to check how it's going, that helped for me. It's useless to email them, don't help at all.
You may want to read this post. I used expirefish and snap names for a domain that wasn't really that great. Buy domains got it instantly. If your domain is in demand don't waste your money on these services.