Running Oracle Apps on Amazon EC2  is going to be easy in near future as full Oracle Software Stack Certified and Supported on Oracle VM on Amazon EC2.
Question you might have is what is EC2 or Amazon EC2 , let try to understand ?
What is Amazon Web Services?
AWS provides flexible, scalable, secure, and cost-effective IT infrastructure for businesses of all sizes around the world.
In other word , it is subscription based service in which :
- Computation of power and storage is available to you on-demand, you just need to pay only for the resources you use…
- It is running on scalable, reliable, and secure infrastructure operated by Amazon Web Services, based on the knowledge gleaned from over a decade of building efficient and dependable infrastructure for Amazon.com.
If you refer details at service page  of Amazon Web Services aka AWS is a set of primitive building blocks to enable developers to build applications and, ultimately, businesses, on our battle-tested infrastructure.
Next question you may have what kinds of building blocks do developers need?
First, you need compute resources . The Elastic Compute Cloud, or EC2, allows developers to rent virtual computers, running in our data centers, and pay for them by the hour. Provision as many as you need - 1, 10, 500, 1000, for as long as you need them, and you pay only for what you use (starting at less than 10 cents/hour).
Second, you probably need somewhere to durably store and retrieve data. The Simple Storage Service, is, well, a simple storage service that allows to store and retrieve objects in the cloud using simple put and get API calls.
You might need to index and query for that data, or create other structured data that you want to query, which is what we built SimpleDB.
Look at the figure below and you can easily find the high level overview and details for there core components.
Amazon Web Services is in global reach and currently operated from four major AWS Regions located US East (Northern Virginia),US West (Northern California),Europe (Dublin) & Asia Pacific (Singapore) whereas AWS CloudFront Locations are Ashburn, VA / Dallas, TX / Los Angeles, CA / Miami, FL / Newark, NJ / Palo Alto, CA / Seattle, WA / St. Louis, MO / Amsterdam / Dublin / Frankfurt / London / Hong Kong / Tokyo/ Singapore.
Understanding Amazon Virtual Private Cloud(VPC) Architecture (Adopted from Amazon )
To understand the VPC high level architecture let understand various discrete elements of a VPC, and a specific data flow to exemplify 1) data-in-transit security and continued 1) AAA control by the enterprise.
- AWS these are represented as "orange cloud" in figure 2 : This is what everyone knows of AWS today.
- Customer's Network these are represented as "blue square" in figure 2 : This is the customer's internal IT infrastructure.
- VPC these are the "blue square on top of orange cloud" in figure 2 : These are the secure container for other object types which includes Border Router for external connectivity. The isolated resources that customers have in the AWS cloud.
- Cloud Router these are the "orange router surrounded by clouds": Lives within a VPC; anchors an AZ; presents stateful filtering.
- Cloud Subnet ("blue squares" inside VPC): connects instances to a Cloud Router.
- VPN Connection: Customer Gateway and VPN Gateway anchor both sides of the VPN Connection, and enables secure connectivity; implemented using industry standard mechanisms. Please note that we currently require whatever customer gateway device is used supports BGP. We actually terminate two (2) tunnels - one tunnel per VPN Gateway - on our side. Besides providing high availability, we can service one device while maintaining service. As such, we can either connect to one of the customer's BGP-supporting devices (preferably running JunOS or IOS).
Amazon EC2 is secured it will have features like signed API Calls and Guest O/S Firewalls and Encryption.Moreover the Regulatory Compliance and Certifications is also well catered for Sarbanes-Oxley (SOX),SAS70 Type II,Pursuing ISO 27001 and PCI and HIPAA compliant applications deployed on AWS. You can check the Security Whitepaper available at aws.amazon.com/security 
Oracle Certification, Support and Licensing
- All products certified on the Oracle Virtual Machine are now Certified on Amazon EC2 managed OVM
- Full Support from Oracle and AWS
- Standard Licensing Policies Apply
- AMIs exist today for many Oracle products
Hoping coming years there will be growing number of companies who are going to deployOracle E-Business Suite on the Amazon Web Services cloud computing platform.