Actually, you don't need the DIV or span in your case. P is already a block element. Use a SPAN if you want part of the P to have a different style than the rest. you also have to make sure your code is clean you had a couple of unclosed tags... that WILL WRECK stuff.. just so you know.
<p clsss="richtext3">Paragraph 1 Paragraph 1 Paragraph 1 Paragraph 1 </p>
<p>Paragraph 2 Paragraph 2 Paragraph 2 Paragraph 2 </p>
<p>Paragraph 3 Paragraph 3 Paragraph 3 Paragraph 3 Paragraph 3 </p>
as far as spacing is concerned, am unclear what you want to happen...
did you want all four P tagsl to be aligned horizontally? or just the last 3?
or are the last 3 actually aligned horizontally, but the last two are a couple of px off?
it would be good if you posted your css