Male on Male Action for Girls.
Besides the comic books and professional anthologies, there are also near-professional-quality zines--doujinshi--which occupy an ambiguous zone between original art, fanfiction, and satire, often ripping off the characters of TV cartoon series to create bizarre, funny, cute, violent, or sexually explicit parodies. (Many are available for sale from a Japanese collector at www.interq.or.jp/tokyo/antique/managa.html.) Popular children's comics and shows like Pokemon or Digiman have always been prime targets for this slick guerrilla art. However, with the increasing interest of multinational corporations in the original properties--which can be spun off into video games, toys, and feature films, as well as comics and TV shows--the traditional climate of indifference to these copyright violations is showing signs of wear.
How Japanese gay people regard these comics is difficult to gauge. Some people find them irrelevant, others downright irritating and offensive, while still others find them cute. Often it's hard to find distinctly gay voices to comment, though I suspect at least a few of the mangaka (cartoon artists) who are assumed to be female are actually men using pennames. (Andromeda's Yaoi Museum--www.animanga.com/andromeda/yaoi/main.html -- has a feature on the mangaka, some of whom are idolized celebrities in their own right.) It's not an uncommon plot twist in the stories themselves for a boy to be "caught" reading his sister's comics, a romantic twist inevitably following his blushing humiliation.
I remember when I had the hots for the heroes of G-Force (available now on video in a more faithful translation as Gatchaman, complete with gratuitous nude scenes) and all the pictures I drew and stories I wrote had to be carefully hidden away. Perhaps the most curious, and touching, aspect of this whole phenomenon is that isolated young Americans have used their shared interest in homoerotic cartoons and fanfiction--stripped by its foreignness of any definite declaration of sexual identity--to form friendship networks. There are lots of individual sites that come and go very quickly, linked together in web-rings. Rhiannon's Why Can't This Be Love (http://bishojou.tripod.com/taito), a Digiman Taichi/Yamato shrine that anchors a Taito web-ring, is one site that will probably be around for a while. There are multiple newsgroups ranging from simple ones for the exchange of kinky cartoon pictures to ones in which the participants exchange translations of entire comics, Which is, unfortunately, the next-best-thing to published English-language versions currently available for many titles.
Among the larger American sites, Aestheticism.com is a huge, participant-oriented conglomeration loaded with glossaries, essays, translations and other links of interest to shoujo manga and yaoi fans. Sakurazukamori.net is a beautiful web magazine, essay-oriented but graphically delightful as well. With an almost academic intensity and professionalism, it's partially a fansite devoted to the CLAMP group of manga artists--the import anime series Cardcaptors is based on their series Card Captor Sekura (tune into www.cardcaptors-uncensored.com for a dedicated fan's complaints about this process). Within Sakurazukamori.net is a subsite called Lipstick Boy (http://sakurazukamori.net/bishounen) that neatly portrays the relationship between modern shounen ai and the courtly homoerotic poetry of medieval Japan, from which the meaning and conventions of terms like bishounen ("beautiful boy"--an equivalent to the Greek ephebe, a youth whose beauty has an androgynous charm) derive. The site also has a CLAMP name generat or--mine is Shuiichirou Soryuu!
Though the big business of bringing Japanese comics and anime to American audiences tends to the tastes of straight teenage boys, the internet has facilitated the cultural exchange of this material on an informal basis. Other than searching manga-oriented home, news and review pages, learning about titles with homoerotic content, and cross-referencing these in a search of sales sites could one possibly hope to find newly available titles of interest. Streaming video sites are advertising anime content but turn over rapidly these days, making specific content difficult to find. Be prepared for something more than a simple search--it's an education, and an adventure. And if you're lucky you can find your way out of the digital world.