arnica is the best thing for bruises. my toddling son has had more than his fair share of knocks and bumps. even the bumps went away within the day and the bruises don't even get to turn a purple or yellow colour.
i got my arnica cream from Bumps2Babes (much cheaper), but you can also get them from Healthquest, Citysuper.
We have a Boo-boo Balm from Badger (got it from Doubibou). It's made with natural ingredients (Fresh Beeswax, Sweet Almond Oil, Tea Tree, Lavender and Rosemary Essential Oils). We use more for the "comfort" factor of applying something to the wound/bruise.
I second Arnica and have used it since I was a small child - it's natural and works brilliantly to speed the healing of all forms of bruising.
I use the cream version on the bub when she has a bump/knock, or on myself (recently I keep misjudging the size of my pregnant stomach trying to squeeze through small places!)
There is also homeopathic tablet version to assist the healing process for severe bruising (e.g. when you get teeth removed etc.)
I get the cream from B2B and the oral tablets from Mannings.
It's true arnica works a dream. Especially for bumps on the head, if you give the homeopathic tablets (arnica 30) if the bump is coming up you literally see it going down. If it is really bad I use the cream as well. You can get both from IMI in Central. Arnica is really good too for stopping the bleeding of a wound...but you can only use the tablet form for this.