Can someone point me to a howto on setting up a simple peer network. My main machine is pclinuxos with a wired connection to a comtrend wireless ADSL2+router provided by my internet provider. I want to connect to my laptop running linuxmint 15 which has a wireless connection.

The first thing you have to figure out is if you can even do an ad-hoc wirless network to your desktop. Does it even have a receiver to pick up the wireless signal or how were you planning on establishing connectivity between the two?

Additionally, you could solve this problem with $20 at your local electronics store and just pick up a wifi router to put behind your isp's router/modem. You wont notice any connection lag as at the very minimum it should be 100Mb/s and I doubt your connection is anymore than 10Mb/s unless you are paying for a very expensive plan with your own dedicated line to the fiber pipe.

Both machines connect through the same router, 1 wired and 1 wireless. The laptop found the printer and SMB4K found Windows machine, both wired. Shouldn't the 2 Linux machines be able to talk to each other?

Yes, all machines should be able to talk to each other.

What IP addresses have you assigned to each machine?

How are you attempting to communicate? Use nmap to see which ports are open.

Only if configured to do so on the router. Routers are locked down out of the box because how many home users will be ssh'ing to systems on their internal network? You will more than likely just need to login to the routers web interface and open the internal ports.