Matt Cutts has some useful insights how to detain if your site was attacked by XSS Exploits, such as performing some searches through Google search to compare the results, this is how XSS Exploits work, you might check this G search too with more details about the exploits along with some hacker info.
Interesting insights, note how many WordPress tips Cutts is releasing in the past…
Check your searchbox for exploits . 1512
