Here are a list of useful resources if you want to create a Web App in Office 365/SharePoint
Garry has produced a series of videos so that you can decide if Access Web Apps are for you. These are from Garry's talk at the ShareThePoint conference in Sydney.
You Are Going To Need Books Like the Good Old Days
If you are an Access expert and think you know all there is to know about Access databases, its time for a cup of tea. You need to start again, you need to understand the building blocks of a web app. You need to read /skim all of the Web Apps section of this book before you open start building databases.
If you are just starting, I would Read Jeff Conrad's book on Access Web Apps and keep a good eye on out for Andrew Couch's book Extend Microsoft Access Applications to the Cloud when it comes out (It will be good)
If you are a developer, Professional Access 2013 Programming is the book. The detail on sharepoint permissions, offsite reading/writing to databases seems very detailed.
How to Try It Out
Microsoft says "In order to try out Access 2013 Web Apps, be sure to choose one of the plans for business: Small Business or Enterprise." To find out more, go to this Microsoft page and look for the row "Access Services".
Ipad Access does not need a Tablet version of Office. See this YouTube video by Garry
In the meantime, Probably best that you sit back and watch a video from the SharePoint conference
This MS page will give you an idea of the new things in Access Web Apps
Learn how to add a filter to a View (used to be called a form) so that only some records are shown when you open a View. This is done with queries. Because not all the old query tricks work, build up the complexity piece by piece.
and filter the data using a Popup Form
When you import into an Access App, you cannot directly add to an existing table
The Difference Between Access 2010 Web Apps and Access 2013 Web Apps
Training Videos At Microsoft
If You Cannot Find The Web App after you have closed down Access 2013
Web apps are stored in .accdb files (that can only be opened in A 2013). You may have trouble finding them, if so look for a hidden folder
where YourLoginName is your windows login name. You can move this accdb file around.
Where Did SQL Editor, Update, Delete and Append Queries Go
These are features that are not currently in the web apps 2013. For now you will need to learn data macros or cleanup on the desktop and import and copy and paste.
If you are deleting data, you can select the records and press the delete button. Unfortunately this doesn't apply to all the records you select. Seems like about 200 rows maximum. If the Loading ... appears for a while, nothing is going to happen I think.
Using Excel With Web App Data
Visual Studio + Java API for Office Wall maps
The most important thing in the next link is Access is shown on the map :)
Try an Access Web App Without A Login/Pwd
The UK Access users group has an Access web app in their public web site here. Click on Explore at the top of page to see the app
How Big Can The Access App Get
Search for Sharepoint App in this Microsoft Sharepoint page and there is discussions on this page Notes on Backup
Reviews of Access Web Apps
A couple of pertinant points and some insight into Web Apps
How to change regional timezones so you get the correct default date
Note: I am still having troubles with this but I am sure this worked for a while till I added my own domain to the SharePoint site