Author Solutions (owner of the iUniverse, Xlibris, AuthorHouse, and Trafford brands, and the power behind the outsourced self-publishing divisions of Harlequin and Thomas Nelson, among others): BookTango, an ebook aggregator for self-published authors.
BookTango, which is still in beta, offers DIY ebook conversion via its online ebook editor (your file needs to be formatted to BookTango's specifications), and distribution to a variety of platforms, including Apple, Amazon, Barnes and Noble, BooksOnBoard, Google, and Kobo. There's also a cover design function, ISBN assignment, and of course, payment processing.
This basic service package is free. For the $49 package, you get the basics plus conversion services (if you don't want to DIY), the ability to include images, fancier cover design options, and a free download of your ebook. There's also a $189 package; the only difference between it and the $49 package seems to be that BookTango will "handle the paperwork and get your e-book properly protected under U.S. copyright regulations." Since copyright registration is not only very easy to accomplish yourself, but costs just $35 if you do it online, there doesn't appear to be a single reason to spring for this.
BookTango says it pays "100% of net" on books sold through its own bookstore, and "90% of net" on books sold via other retailers, and claims its royalties are "the biggest in the industry" (hmmm...not so much; see below). Before you get stars in your eyes, what those numbers actually add up to is that for BookTango bookstore sales, "net" is what's left after BookTango takes a 30% transaction fee (so "100% of net" really means 70% of list); while for retailer sales, "net" is wholesale less a 10% BookTango commission. Retailer discounts can be as much as 60%, so in some cases authors may be making as little as 30% of list.
How does BookTango stack up against other aggregators, such as BookBaby, EbookIt, and of course the grandaddy of them all, Smashwords? You can certainly get better financial terms. Smashwords, for instance, charges no fees, and pays 85% of list for sales from its website and 60% of list for sales through outside retailers (so much for "the biggest royalties in the industry")--but it's truly a no-frills service, and not everyone loves its Meatgrinder conversion engine. BookBaby has no free option, and both its packages cost more than BookTango's--but it doesn't take a commission on what it receives from retailers, so authors get the full wholesale price. EbookIt, on the other hand, is more expensive than BookTango on two fronts--its upfront fee is higher, and while it pays a bit more for sales through its website (75% of list), it keeps a bigger commission (15%) on sales through outside retailers.
Comparison shopping is essential to find the service that best fits your needs and finances. Overall, though, BookTango looks like a reasonably competitive service--as long as you read the fine print, ignore the ridiculously overpriced $189 package, and are prepared to resist the expensive marketing services BookTango's parent company wants to sell you (these are prominently featured on BookTango's website). Authors who choose BookTango should be aware that Author Solutions is a relentless marketer, and should expect to be solicited for other Author Solutions services--including, very likely, a premium membership in AS's Author Learning Center (cost: $149 per year; trial subscriptions are included in all BookTango packages).