Any of you guys that are into Differential Calculus, check out the Wolfram apps - their Advanced Calculus is awesome. You need an Internet connection (it's hosted on their 'super computer') but differentiation, integration (single, double and triple integrals), vector fields, 2D and 3D plots (contour or surface plots), the list goes on and on - in the UK it's only £2.99 (what, are these guys crazy??), so I guess that's about $5-6 in the US. Now that's the app that I'd want on my Desert Island (see the other thread!) - oh - no Internet on the desert island - OK, pull out the HP-35....
Tim