Tangerine Dreams is a guide to shoujo manga and anime, josei manga, and Korean girls' manhwa published in English. It was last updated March 2007 and thus reflects the state of the market at that time. I have been unable to keep up with all the new releases since, but I hope you will find the site of use as a starting point.
Many people are confused about which series are shoujo and which are guys' shows featuring female characters. The definition of shoujo manga is simple: it is manga published in shoujo magazines as defined by their publishers. Shoujo manga are Japanese comics for young and teenage girls and Josei manga are comics for young women. Manhwa are Korean. They are primarily created by female artists for a female audience - although the editors and publishers are largely male, and the type of stories which get published inevitably are shaped by these male gatekeepers' tastes. Shoujo anime are obviously the animated versions of girls' comics, although there are a few original animated productions not based on a pre-existing manga.
You can purchase American licensed anime and manga from general online stores like Amazon or specialty anime and manga retailers like The Right Stuf. The books and DVDs listed on this site are linked to Right Stuf. I like Right Stuf myself because it has regular company sales (check the front page, reachable thru the previous link by clicking the "RightStuf.com" graphic) and Weekly Specials. I've heard that Canadians can try asking RightStuf to supply a filled-out NAFTA form to bypass customs duties, although I have yet to try this myself. Due to the everchanging nature of anime DVD releases and the rapidity with which they are released and rereleased as singles, DVD box sets, thinpaks, "remix" and other discounted editions, before eventually going out of print, you should always visit AnimeOnDVD to see what's been released and is upcoming for a series. This is also the reason why I have ceased listing DVDs individually: all links point to either the Right Stuf Search page or to an item category page so you will always see what's available now.