There are definite similarities, though I think Stoicism and Buddhism have fairly different philosophical motivations and conclusions. In particular, Stoicism tends to emphasize rationalism more, and is less suspicious of attachment to the self (if anything, being in favor of cultivating the self). It's a fairly complex topic and there are a dozen variants of both Buddhism and Stoicism, so that's probably wrong as a generalization, but it seems to me to be where the emphases are.

This random Google Books result expands on a comparison along those lines: http://books.google.com/books?id=yLQ-GQTcwVkC&pg=PA67