I just found out that my alternator needs to be replaced, 2001 Vovlo S40. Does anyone have a ballpark idea what this will cost-parts & labor?

depends on who is doing the work? that is a seriously obvious answer. dealership or private? new or used? under warranty? a little more info would be helpful.

Another option would be to get it repaired if you can get it off easily and cost is a factor.
Few years ago i was told i needed a new alternator and it was big money,took it to an electrical firm who tested it and soldered a diode on that had come detached .All it cost was a few $$

Its not under warranty. I will be getting it done with a private mechanic.

then it will cost going rate by the hour. in new york, that is 95-98 per hour. +/-. now, if you buy the alternator and have them replace it for you, it will be cheaper since the mechanic won't rip you with the mark up on the unit. weezy brings up a good point, if you are mechanically inclined, do it yourself. serious dosh saving there.