For X-Cart version 4.1.x please go here as the csv guide below no longer applies
One of the biggest issues people seem to have with X-Cart is understanding how to import products via CSV. The X-Cart manual is a good basic guide, but it doesn't go into quite enough detail, particularly with thumbnail images. I have attempted to put together a step-by-step guide, along with some sample files which will hopefully help with the learning curve. You can download this guide here:
X-Cart CSV Import Guide
Note that this guide is only for 4.0.x, as some of the Column names are different than earlier versions. This has recently been updated to reflect some changes in the csv structure (including replacing manufaturerid with manufacturer). Please let me know if you find any issues.
Hope this is helpful!