Hey LJ -
You can start by doing a search on "clen" and limit it to the women's board. You'll find reams of stuff on the topic. Or better yet, get your girl on here to educate herself.
Before she goes diving into using pills to lose weight, have her re-examine her diet & training. If those aren't in check, the pills wont' help anything. Just make her miserable. Also you wouldn't want to do a continuous cycle of clen for 6 weeks.
She'll probably get great results w/ just ECA and a tight diet / training.
Please don't let her think that there are quick fixes for losing weight because whatever she does, her body has to adjust to it and it takes time.
Can you or she post her diet & training now? That's the easiest & safest place to start.