Weird joins coming up with subsurf I am finding that at certain spots in my mesh, when I've applied subsurf modifier, I get these weirdly sharpened / extended edges on some joins, but not on others. See the photos for what I mean. 

I've tried playing around with adding edges and loop cuts but that doesn't seem to fix the issue. 

Here's another example of this, may be a different problem, but this was seems to actually be making creases of some sort. 



Blend file is here: http://www.pasteall.org/blend/33247
Any help much appreciated, Thanks!
The artifacts you are talking about are results of a bad topology of your mesh. The subdivision modifier is very sensitive to your edge, vertex and loops placement. The mesh should be ideally all square faces (no triangles or ngons) and have similarly sized polygons around creases.

There is a lot on the internet about mesh topologies (examples etc.), search for "mesh topology" or "mesh edge flow". Here are some tutorials from CGcookie.

In your model you can start by removing ngons, having all quads, and spacing even edge-loops around your creases: