There are many cross-browser variations in the default display of <ul>, <ol> and <li>. There is no standard, and no convention used by all the major browsers. So, I think it's a best practice to explicitly declare rules for these three in your css whenever you use them.
Even then, you can run into problems when you have a floated element to the left of your lists and list items. Different browsers calculate left-margin in various ways in that situation. The only resolution I've found is to give up on consistent cross-browser display and work with the css rules until each browser at least gives a usable version of the page.
if you set margin: 0; and padding: 0; onto the list it will move the list item to the edge of the div.. the bullet is still there but by default it is set "outside" of the <ul> container (with approximately a 15px width) this bullet is no longer there according to IE, but it is really ;)
setting the list-style-position: inside; brings the bullet inside of the <ul> and may solve your problem.