Setting up own domain and mailserver

[RL]

This has to be the most compilcated subject to me.  I just purchased a
new domain from godaddy.  I have a few questions I am not totally
clear about yet.

1. I have adelphia cable internet.  I would like to get a dyndns or
no-ip.com account to have a static IP for my new godaddy domain.
Simple enough.  However, I would like to also do my own DNS to learn
more about it.   Will I be able to do this if I set my nameserver on
godaddy to my box's dyndns address?  And from there can I set up A
records, MX Records, etc and all that good stuff?

2.  What about reverse DNS?  Could I possibly do that on my box?  

3. I would also like to run my own mailserver for that domain (again
to learn).  Would I be able to do this and send receive email from/to
name at mynewdomain.com?  I know most ISPs block port 25 and no-ip.com
has a pay service called mail reflector that can get around this.  Is
this necessary?  Why couldn't I just set up sendmail to use a port
other than 25 like 8080?

Thanks.  Again, this stuff just confuses the heck out of me.