David says:

Sorry to anyone I owe emails to!  Our hotel is blocking outbound SMTP, and my iPhone’s data roaming doesn’t seem to want to work here.

I’ve had this problem too while traveling. It’s nice to know that hotel WiFi is equally moronic the world over. I’ve had occasional success, however, with SMTP servers that I connect to over SSL.

There are two benefits to using encrypted mail connections. First, SMTP over SSL uses a different (often unblocked) port than normal SMTP. The second is that SSL makes sending and receiving mail over a shared or untrusted network slightly more secure. (For those of you using gmail with a desktop mail application, here’s how your connection settings should look)