I am going to buy Mass Effect 2 now that I have time. While looking at the dragon age case I saw that the free DLC code expires in April. It didnt say anything about an expiry date for the cerberus network on the ME2 case. Anyone know if there is one?

I believe there is for codes that are included with games. But, I would like to note that I am not entirely sure and could be wrong about whether that specific code has an expiration date on it. I just have a feeling that you missed it. But, I wouldn't lose too much sleep over it, nothing on the cerberus network is all that good.

I wouldn't be too worried anyway. Having just completed the free DLC myself I can safely say it wasn't very interesting. The arc gun is pretty neato but Zaeed isn't the best character and the Normandy crash site was a bit of a disappointment.
 
As you'd expect though the recent Overlord DLC which costs money looks a whole heap better.
 
Also while I'm on the topic how lame is it that you need "Bioware points" to purchase Overlord for the PC? I would have bought it already if I didn't have to sink more money into points than is actually needed for the DLC. I've always hated this "points" idea since Microsoft introduced it for Live, it's only purpose is to obscure the transaction a little in an attempt to get you to spend more money. Anyway EA lost my purchase as a result...

Just bought it and no problems :)