You can directly write to the Publications Manager of PLoS Computational Biology(ploscompbiol@plos.org). Mostly, they intertain, an would love to hear suggestions for possible new articles sections. I am sure they will let you know how you script/pipeline/tool article may fit in.
The following is a list of journals which accept submissions that are primarily about the software, and not necessarily on new algorithms or new science. There is an expectation that the use of the software will enable new research to be carried out. This list of journals is not exhaustive - if you know of others, please let me know.