today is probably only of interest if you use librarything and own a g1, and it’s a bit late i guess, but here we go anyway:
sounds like it might be an instructional porn video, ne? (^_^) anyhow my little sister and i took a couple of g1s into my lair and got to work. 
first off, of course, you’ll need a g1. it’s usefuly for more than just this, and i highly recommend it~ (^_^) second off, you’ll need the Barcode Scanner app for your phone. also useful for more than just this, and also highly recommended. the other thing you’ll need is the app called scan paste. this takes the input from Barcode Scanner and puts it on your clipboard. this is the important part, as you’ll see in a minute. i’m assuming you already have a librarything account. if not, get one! it’s awesome~ i’m also assuming you already have books. you should get (more) of these, too, whether you have some or not. more always = better when it comes to owning books. having thus assembled your goods, the process is as follows: open scanpaste, hit the Scan Barcode button, and scan in the barcode on your book. you want the one that actually represents the ISBN of your book, which should have the ISBN above it, and should start with 978. scan in as many books as you’re comfy with, ScanPaste will put them all in the clipboard, so unless you’re hoping to scan in 1000+ books in one go, you’ll probably be fine. i did mine 50~100 books at a time without incident. 
once you’re through scanning books, hit the Copy to Clipboard button. you should get a little notification telling you it was successful. from here, you have two choices, you can either go directly to the librarything website on your phone, or you can email yourself the ISBNs that you’ve just scanned in and go to librarything on your computer. i chose the latter, coz librarything doesn’t look so swell on a tiny little screen. (i say, with my 10″ eee netbook as my main computer…) from the librarything main page (after you’ve logged in, of course) click on the Add Books tab, and scroll down the page until you find the “import books” link at the bottom of the left-hand column: 
click on that link and it should take you to a screen with lots of blue: 
paste your ISBNs/barcodes into the box labeled “Paste Text” and then hit the Grab button. your ISBNs will go into a queue of ISBNs that librarything is looking up at that moment, and it may take some time, depending on how many people are ahead of you and how many codes you put in. the nice thing, is that you don’t have to stay on that page (or indeed even logged in) while librarything is looking your codes up, so feel free to browse the wide wonders of the internet whilst you await the outcome. when you come back, you should find your library expanded. you may find some duplicate entries, so i recommend double checking your newly enlarged library, and if you go back to the import books link, it will tell you how many of your codes failed, so you can go back and find those books and enter them manually if you’d like. i find that as long as you had a code that started with 978, it’s very very rare for a code to fail. i had some japanese books with 978 ISBNs that weren’t found, but i don’t think amazon.co.jp was one of my top three sources, so if you have a lot of foreign-language books, you may want to check that out. when i was through, i went from 61 to 279 books in my library. it was annoying to put them all in the appropriate Collections (a new tagging-type feature on librarything) but it was so worth it, as i now have a delightfully organized record of all the books i own, accessable from anywhere with internet access (including on my phone!). 
