The ps2dev.org forum has an interesting thread on porting existing applications to firmware 3.60 - though there are reports that many applications already run on 3.60 without any updates:
Development for the Slim and 3.60 is largely the same. Since it’s not 1.50 anymore, you’ll want to set BUILD_PRX=1 and PSP_FW_VERSION=360 in your Makefile. Since the executable is now a PRX, the default heap size will be only 64kb and you’ll want something like PSP_HEAP_SIZE_KB(25000) in your C file to give malloc() a bigger pool. The extra memory is located in a different partition as described here, which newlib isn’t set up to use at the moment.