Difficult question to answer. The general rule is no, the two programs are built using completely different engines so the file formats are pretty much incompatible. However, the simpler the layers (i.e. if it's just a vector shape with no layer styles applied) the more luck you will have trying to force the other program to open it.

Feel free to try a few of the dodgy looking programs that google throws up but I've never heard of a full-proof conversion tool for PSD -> PSP. You might be better off saving each layer as a seperate lossless image file and importing them in separately.