Customizing widgets in a widgetized sidebar

Hey guys,

I’ve themed and customised my own blog and it’s all been successful so far. I’ve also managed to customise my ‘widgets’ in the sidebar in 2.3. However, when I widgetized my sidebar for 2.5, I don’t see any way to change the content of my widgets like it was possible before (removing lists from Meta being the main issue or removing the title completely)
So I thought if I could find the code for a certain widget itself I could remove all the li or ul tags or whatever it is (as I see them in the source code of my site). However, I have no idea where to find them.

Thanks in advance.