I know Google tends to penalize sites for excessive links on a page (>100 links), but if those links are to within your own site e.g. related posts, popular posts and so forth, does the penalty still apply?
I'm guessing you are refering to PR penalties. From what I understand, you will not be penalised for inside links, but they will just not count towards increasing your PR.
I think there is no 'penalty' but little 'devaluation' is done if content to links ratio is very low.
The ratio of text (Content, article or anything which is not an image as well as URL) and hypertext(Links) on a page. If you have more links than the simple tex, your page may get devalued by google.
translation: the page on which you have 100+ links won't be found in google very often, but the other pages won't be affected. Having a sitemap type page is very useful for your visitors, and google WILL index that page, so for the site as a whole it is no problem at all to have that one page with a 100+ internal links.
Thats bull, because then almost all teh forums on the interent would be penalized, so yeah i dont think so, unless you had 1530501503 links