I am playing around with the demo right now but right now I have a separate atom server as the DHCP/DNS server. I have been thinking of switching to using the RouterOS, but I do like how I can access my home computers by computer name rather than IP address.

With the exception of manually adding static leases and static DNS entrys is there another way to do it?

Yes, RouterOS supports dynamic DNS updates
http://wiki.mikrotik.com/wiki/Manual:Tools/Dynamic_DNS

Thats good honstly:)

How about the DHCP Server, does it support updating the DNS? Looked over http://wiki.mikrotik.com/wiki/Manual:IP/DHCP_Server but I cannot find anything to put a secret key or even server info in it.

DHCP server is not meant for such tasks so it cannot update any DNS records.

Hi,
Is there a way to have the build-in dhcp server use the tool dns-update to update the dns server ?

Only if you write a script that reads DHCP leases and updates DNS.