Just to add a small detail. Often http servers will log the entire GET request but will not log the POST data. This doesn't make POST more secure when transfering data to the server but there's no reason to leave the data laying around in log files for someone to scoop up off of a backup tape or something.

It has been mentioned LWP will let you POST data to the server. LWP is probably the better choice but the command line programs wget and curl will also do POST (get the newest versions though).