You subscribe to a mailing list and are sent messages by email. Mailing lists are the best way to automatically get the latest info.
Messages are sent to you either immediately when they arrive at the distribution site (reflected mode), or are sent as one big message per day (called a digest) containing all the day's messages. With a digest you don't get the messages in real time, but you also don't get a lot of mailing list messages mixed in with your other mail. Not all lists offer digests.
To subscribe, send mail to the subscription address and fill out the message appropriately. You can often send a help message to the same address. Be aware that some lists are run manually by (overworked) humans, so be polite when you write.
For lists run using listproc or listserv you usually give your real name after the list name when subscribing. For lists run using majordomo, you typically don't need to give your name or email address when subscribing, just the name of the list. For majordomo, you only need to give an email address when your preferred subscription address is different from your return address. With majordomo you can usually get information about a list by sending a message with "info list-name" in the body to the site's majordomo address.