Hi there, I am a newbee too (started this very weekend) and was having the same issue. Resolved it in a very easy way:
All images in your posts will have a style applied, for adding a border to it, for example. Identify this style and look it up in your stylesheet. In the well known Green Marinee template I used, the style for the images is called .main img .
The image style was:
.main img {
padding: 3px;
border: 1px solid #ACE149;
}
and I changed it to:
.main img {
float: left;
margin: 0 10px 10px 0;
padding: 3px;
border: 1px solid #ACE149;
}
This will always put the image in the upper left corner of your post, with the text wrapped around it nicely.
Hope it helped. Succes.