Not knowing what software you are using or how your site is set up it would be hard to give you any advice on how to filter, or limit the use of certain tags, you already have the <P> covered it will wutomatically allow all <P> tags with attributes that you must specify such as the alignment feature which is an attribute of not only the <P> tag but others as well duch as the <DIV> or <SPAN> I suppose you could create a form that produces button that apply only those features you want but not knowing how you site works it is hard to tell you much more.
A link to the site or perhaps some code that shows us just what you have right now would get more responses and probably a means to do what you want.
See the Code below that defines some image icons for use in posting within a form.
HTML
<img src="images/url.gif" border="0" accesskey='h' value=' http:// ' onclick='tag_url()' name='url' onmouseover="hstat('url')" />
<img src="images/img.gif" border="0"accesskey='g' value=' IMG ' onclick='tag_image()' name='img' onmouseover="hstat('img')" />
<img src="images/email.gif" border="0" accesskey='e' value=' @ ' onclick='tag_email()' name='email' onmouseover="hstat('email')" />
<br />
<img src="images/quote.gif" border="0" accesskey='q' value=' QUOTE ' onclick='simpletag("QUOTE")' name='QUOTE' onmouseover="hstat('quote')" />
<img src="images/code.gif" border="0"accesskey='p' value=' CODE ' onclick='simpletag("CODE")' name='CODE' onmouseover="hstat('code')" />
<img src="images/list.gif" border="0" accesskey='l' value=' LIST ' onclick='tag_list()' name="LIST" onmouseover="hstat('list')" />
<br />
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