TACACS or Radius daemon on Linux

[mnolan]

Hi,

We are an ISP running several Cisco 2500s, 5200s, and 5300s as access 
servers.  Currently we are entering each user into each box.

We are looking to set up a Red Hat Linux machine as either a TACACS or
Radius server to centrally validate all our users.

Does anyone have any experience running a TACACS or Radius daemon
on Linux?  Where is a good place to find a Linux TACACS or Radius 
daemon?

I heard that although TACACS is a Cisco product, Radius has more 
accounting and statistics capability, runs well on Linux, and will 
validate for Ciscos.

Any help would appreciated.

Thanks,
Mike