Google PageRank is calculated by the number of internal links to your site and Google has repeatedly stated that the number of outgoing links from your site have no direct implications on your PageRank.
Fair enough. But I’d invite you to look at this from a different perspective.
Rather than bothering about the number of outgoing links from your site (that you may think will dilute your PageRank), think about the quality of outgoing links on your site.
Let’s say you have a blogroll of ten links. You linked to them because they were your friends. Fair enough.
But what if one of them bought text links, and eventually get penalized ? You would land up in their “network” and this could improve the possibilities of getting you in to a bad reputation.
So rather than cutting down on the number of outgoing links on your site, make sure you link to only trusted sources. If at all you would link to someone without a reputation, use the nofollow tags, so that the crawler gets the signal.
So linking to other sites won’t reduce your PageRank unless you are not sure about whom you’re linking to. Its not the numbers but the quality of each link that matters.