Sent you a 0.1 BTC tip for that (is it similar with POP3 btw?).
Thanks, that's generous - forum advice is normally free :-)
POP3 sadly is a totally different beast - unlike some other line-oriented protocols such as SMTP, NNTP or FTP, they have a different command/response structure. In particular, it depends on the command that was sent whether the client can expect a single-line or multi-line response. However, parsing the responses is pretty easy in POP3: The first response line always starts with +OK or -ERR (additional text can follow, a client should not interpret that but it can give useful additional hints during debugging).
If a command expects a multi-line response, the server sends a line containing just a single period as the last line. The client should check the first character of each received line, if it is a period but there's more stuff in the line it should drop the initial period (the server can use this to escape lines containing a single period). This is basically the reverse of what SMTP does in the DATA command.
I found the RFCs for these standard protocols to be pretty readable. POP3 is described in
http://www.ietf.org/rfc/rfc1939.txt.
Onkel Paul