There are several websites that have backstitch and cross stitch fonts, so you can input your text, choose the font, and it will generate a pattern for you. Personally, I like this one: http://www.stitchpoint.com/eng/tool/alph/cross-stitch-writing-tool.php

You can also buy books that have different alphabet patterns in them and put together the saying yourself.

For the drawing, I use pic2pat.com frequently for art that I want to turn into cross stitch charts. It lets you specify the fabric you are using, the finished size you want, and the number of colours of floss you want to use. It is super easy to use and generates a PDF pattern that you can print or use from your computer or phone or tablet.

Good luck with your project!