Yes, you could update personal sites. To look for software updates available, click on Help > MyEclipse Configuration Center > Dashboard tab > Software Updates or under Software tab > Software Updates Available. All the software updates are listed under Updates Available. On the right hand side there is a yellow arrow, you could click that to re-check for updates.
To delete personal sites, open MyEclipse Configuration Center > Software tab. Under My Software > Personal Software, right click on the personal software to be deleted and click on [remove].