Okay, it has been asked for, so I'm starting it. Post a question, get answers.

Post a flame, get deleted.
Can kjk be encouraged to post the mini-faq that has already been started in another thread in this sticky?
of course! Feel free to correct, edit, complain
I'm looking at presenting the information based on how people may search for it...i.e. "Can I read my Kindle books on an iPad?"


DRM Formats, Vendor Specific:
iBooks (Fairplay ePub)
iBooks

Kindle (various formats)
Kindle App, by Amazon (iPad and iPhone apps available, no sideloading)

Barnes and Noble (Adobe DRM-ADEPT Variant- PDF and ePub)
Barnes and Noble eReader Apps, by Barnes and Noble (iPad and iPhone apps available, no sideloading)

Borders Books (Adobe ADEPT(?) PDF and ePub)
Borders eBooks for iPhone and iPad

Kobo Books (Adobe ADEPT(?) PDF and ePub)
Kobo Books by Kobo (also Borders)

Sony Books (Adobe ADEPT(?) ePub)
Txtr, by Txtr (iPhone app available)


DRM Formats, General:
Adobe ADEPT (PDF and ePub)
Kobo, by Kobo (iPad and iPhone apps available, no sideloading)
Txtr, by Txtr (iPhone app available)


Non-DRM Formats:
ePub
iBooks, by Apple (iPad app available now, iPhone app 6/21)
Stanza App, by Lexcycle (iPad and iPhone apps available-thru iTunes)
IBIS Reader, by Threepress (HTML5 based, no app required)

PDF
Stanza, by Lexcycle (iPad and iPhone apps available-thru iTunes)
Cloudreaders by Cloudreaders
GoodReader by Good-i-Ware
iBooks, by Apple (for both iPad and iPhone on 6/21)

Mobi
Stanza, by Lexcycle (iPad and iPhone apps available-thru Stanza Desktop)

PDB
iSilo by iSilo (iPad and iPhone apps available)
Stanza, by Lexcycle (iPad and iPhone apps available-thru Stanza Desktop)

LIT
Stanza, by Lexcycle (iPad and iPhone apps available-thru Stanza Desktop)

CHM
Bookshelf by HPC Technologies (iPad and iPhone apps available)


Other:
Comics (CBR, CBZ)
Stanza, by Lexcycle (iPad and iPhone apps available-thru iTunes)
Cloudreaders by Cloudreaders
Comic Zeal by bitolithic.
Bookman, by Bookman Lab
Marvel Comics by Marvel

Unsupported:
Sony (LRF, LRX) by Sony. (deprecated)
here as well , thanks, nikkie!
Nice kjk

I bet this helps some folks....
Sony reader shouldn't really say unsupported... Or maybe unsupported natively textr can read the books after all.
And if used with full force could be a very good option(haven't tried that myself though as don't have txtr)
Kjk

Thanks for the wiki link. We'll use this thread as a way to gather in more FAQs and you can update if needed.
My IPad is great, but twice now I have checked the time on its clock and it's an hour or two slow. Has anyone else had IPad clock issues?
toomanybooks, I haven't had any clock issues-but I have the 3G version, which I think synchs automatically to an accurate clock..somewhere

Do you Date and Time set to Set Automatically in Settings/General?
Love it! Would like to help out if I can.
I've got the WiFi only version, but my clock is absolutely accurate. I've got WiFi on almost all the time and browse the web frequently a few times per day; maybe this makes the difference...