Dmitry, investigate Asterisk (e.g. www.trixbox.org) and devices like Sipura 3102 or similar. Asterisk is open source = free. You won't need an answering machine, Asterisk can handle heaps of simultaneous voicemail instances with all the "press 1 for sales, 2 for service" etc stuff. You can have different answering options for each line or different responses depending what state they are dialing from or if it is an important customer or your wife's cellphone etc. You can also get a very cheap or even free extra voip line (e.g. www.galaxyvoice.com, I've got a free MA(!) number with free voicemail, 60 minutes/month free national calls, very cheap national and international rates... and I can be making 3 outgoing calls via this voip and it will still ring if somebody calls in). Total cost for the Sipura devices < $200 for 2 normal phone lines and 2 normal internal extensions, you can use an old 386 desktop for Asterisk. If you need more extensions you can buy IP phones for as little as $50 and just plug them into your network for extra extensions.