Need help to setup Asterisk as a PBX


I installed asterisk package (v11) from source (Without DAHDI) on my CentOS 6.5 (x64) box.I created few sip extensions which works fine internally. Now i have few analog phones and i wanted to integrate them with my asterisk box. So how can i do that? Do i need to buy ATA’s for that? Any help greatly appriciated.

ATAs, although replacing the phones may be cheaper.