To answer your questions, yes there is a speaker on the iPod touch. However, it's a low output, beep-only speaker. While you can set alarms, you're most likely not going to hear them unless your iPod is not muffled by anything and the room is completely quiet. I definitely would not count on it reminding you for anything important.
Regarding a lock, I just looked on mine, and yes it does have the same lock as the iPhone.



» Alarms on the iPod touch ... Last Reply: 9 months ago by bioneural.
Just want to point out, alarms can be set through to go through the headphones or any external audio source you have connected. So, your iPod could be used to wake you up if you connected it to something before you went to sleep. It could also be useful for reminders and such if you were in an office environment or whatever, and had your touch connected to a speaker dock or something during the day.
Coming from a Palm device for PDA functions, I don't really find the missing useful speaker a huge loss. I never used the alarms to begin with because I was always at school or in some environment where it wouldn't be socially acceptable to have an alarm sound. So, it's no big deal for me.
What is a big deal is the PDA functionality is spot on and will get even better with the SDK later this month. Having one device that is both great as a PDA and great as an MP3 player has been perfect for me.