I'd start laughing, but it'd be mean.
In early March I signed up for Vonage, my current provider (Verizon) had all sorts of issues with the line, physical ones they refused to touch until June that caused my DSL to be worthless, and all sorts of static on the line. I told Vonage to port me in, they said no problem.
At the end of April early May (2 months) I was finally ported in. They kept giving me a runaround, and their CSRs are basically worthless.
A few things to keep in mind:
1) Keep on top of them. It does NOT take 4 weeks to port like they claim, but it could.
2) Make sure you don't have DSL on your current line, I switched to cable so I didn't care that the port would cancel my Vzn service including DSL, but Vonage was dumb enough to stop the port because they saw DSL on the line. I had it removed and that fixed it.
3) If there's a problem, they won't let you know. I waited a month before contacting them, turned out 3 weeks prior it had been stopped, no notice from them. They don't email you updates or call you, so you have to keep on them.
4) If you don't have DSL, go ahead and put the port in, fill out the form, and fax/mail it to them or whatever. Wait a few days and call them and make sure it's being processed. From that point on call every week to check on it.
5) Get names of CSRs. If you email them, you'll get a response from
port@vonage.com, with NO name in it, no way to track down who sent it to you. They were generally one line responses with no info or help at all in them. I finally got pissed off enough to send them a fairly nasty (but no swearing, I was mad not rude) and got a response back that was formatted and had a name on it, but that was the only one. Some of their people are obviously lazy and aware that their names don't appear in emails, so you can't get them fired for not helping you. Call them, get a name, and keep track so if somebody does/says something that's totally wrong or screws you over, you have a way of tracking it.
Realistically it shouldn't take you more than a few weeks to port over if you don't have any problems, they do give you a temporary number in the meantime, and until your port goes through your old service remains. I dropped down to a basic $18/month deal with Vzn until then, so incoming calls would stil work, and made all of my outgoing on the Vonage system. It works wonderfully now, not a single issue with it other than the 4 hour limit thing (it hangs up after 4 hours in a single call, to prevent phones off the hook from wasting your minutes), and I have a virtual number where my fiancee lives so she can call me for free. Very much worth the headache.