Honestly the easiest way to start is still graph paper and pencil.

Once you get a basic layout, you can try the Ikea planner.

I use a graph, downloaded from the 'net, and opened in Microsoft Paint program. For me, it's much easier to draw a box, then zap it with the back arrow, if it doesn't look right. Also, boxes can be captured and moved around in Paint--I find that much easier than erasing and re-drawing with a pencil.

Ikea and lowes both have free kitchen planning software

I use Microsoft PowerPoint. I downloaded graph paper, created different sizes of ranges, sinks, refrigerators, etc., based on the graph paper scale and now just copy and paste and move around items. I use boxes for cabinets.