Thanks to the many free and affordable iPhone apps that are now available, small businesses can manage and promote their products and services more efficiently and effectively than ever.

Recently, we told you about 15 awesome Android apps for small business. Most of the apps in that list are also available for the iPhone (such as Box and Square), so check out the Apple App Store to find compatible iPhone apps.

For even more useful apps, try the following 10 additional iPhone apps for small business. Each of these apps can help your small business in specific ways. Whether you need a tool to help you keep track of your thoughts, your accounting, or your projects, there really is an app for that!

Productivity and Organizational iPhone Apps

As more and more people use their iPhones as bona fide business tools, Apple has responded to this emerging trend with a variety of powerful business apps. Here’s a selection of some the more versatile iPhone apps for productivity and organizational management.

1. OmniFocus: There are many task management iPhone apps, but if you’re willing to invest under 20 bucks, then OmniFocus is one of the best choices available. A good free task-management alternative is the EasyTask Manager app.

2. Kayak: If you travel frequently for your small business, then you could probably use an iPhone app that helps you make and manage flight, hotel, and transportation reservations quickly and easily. The Kayak iPhone app is free, gets great reviews from users, and was the “People’s Choice Winner” for best mobile traveling app in the 2011 Webby Awards.

3. Evernote: The Evernote app makes it easy to keep everything organized, including notes, lists, pictures, audio recordings, and so on.

4. LastPass: One of the best password management apps available is LastPass. The LastPass app for premium account holders makes it easy to log into any of your online accounts with a just a couple of clicks from your iPhone. If you’re like most people and have dozens of usernames and passwords to manage, then this app is essential.

5. Instapaper: When you’re surfing the web from your iPhone and stumble across a great piece of content that you don’t have time to read, save it for quick access later with Instapaper. The app also formats the content for maximum readability on your iPhone screen. It’s an incredibly handy app and costs just under five dollars.

Sales, Marketing, and Financial iPhone Apps

Being more productive is important, but making sales and adding to the bottom line is the goal of every business. The iPhone has you covered with these very useful sales, marketing, and finance apps.

6. Vignature: If you need to get client or business partner signatures on the go, then Vignature is a great iPhone app for you. It enables you to electronically capture signatures on PDF documents such as quotes, contracts, and so on.

7. Keynote: You can create, edit, and show presentations to clients, business partners, and more directly from your iPhone with the very affordable Keynote app. Keynote is also fully compatible with Microsoft PowerPoint.

8. QuickBooks: If you use the popular QuickBooks accounting software to manage your small business finances, then the QuickBooks Mobile iPhone app is a great choice for you. There is also a PayPal iPhone app as well as a MiniBooks Lite for FreshBooks app for people who use FreshBooks for client invoicing.

9. Free Conference Call: You’ll never pay for a conference call with clients, business partners, or employees when you use the Free Conference Call iPhone app. It enables you to schedule and hold conference calls, free of charge.

10. Ustream Broadcaster: You can stream video of live events from your iPhone and notify your online connections about it in advance using the Ustream app. Video streams are also saved as recordings, so you can promote and share them later.

As you browse iPhone apps in the online app store, be sure to read the reviews to find the best options. Also, scroll down to the bottom of the page for each app. There you’ll find related apps that other people have downloaded listed in the “Customers Also Bought” section. This is a great way to find more apps that can help you run your business more efficiently.

[Image credits: corebasis, Wesley Fryer, David King]