Regular expression for correcting proper nouns

Hi All, I'm looking for a simple was to correct a list of proper nouns given all in lower case! For example given $string="london paris rome"; I would like "London Paris Rome". However there is one cavet; if the word already has a captital anywhere in it, it should be left alone!!! Is there a soultion using regular expressions? Also is there one for removing multiple spaces? i..e given "A B C D E" it would give "A B C D E". I have never used regular expression before and thought that if I had some examples like these, I could go from there. Henry