HTC Desire, Froyo - Gmail hangs when sending attachments
I've found that Android experiences random hangs and lockups when there are less than ~20MB of internal memory. In particular, I've found that on startup there will be a few force closes from the latin keyboard and the system; also the phone becomes noticeably laggy. When there are less than 10MB, the phone is so laggy that it becomes totally unusable. You might want to clean up your internal memory and see if it helps with your problem.