The best to start with iSpike is a draft of a recently submitted paper: LazdinsFidjelandGamez11_iSpike.pdf, which describes the motivation behind iSpike, integration with other software, spike conversion methods, and performance and accuracy measurements.
The first version of iSpike was created by Edgars Lazdins, whose project report contains further background information and more details about the first version of the software architecture.
A short manual with instructions for installing and using iSpike is available here.
Source code documentation is available here.