Hold virtual meetings from afar using the free app Join.me. It combines voice conferencing with screen sharing, allowing people to present and share files with one another from any device. Prefer seeing people’s faces? Appear.in, also free, lets up to eight people join a videochat from a desktop computer, mobile phone, or tablet. Set up a virtual room in advance, and anyone can join by clicking on a link. It’s not necessary to even register.

Project management

Multiple services aim to help you keep projects and teams on task when you’re away from the office. Trello is free and ideal for managing freelancers or organizing web content or a sales pipeline. It creates virtual whiteboards so you can see a team’s progress on a to-do list. Need more? Intellinote, which costs $10 to $20 per user per month, lets you do things like store documents, files, emails, and reports; track due dates; monitor progress; and fill out forms and sign them electronically. For $29 to $49 per user each month, LiquidPlanner can assist you in organizing hundreds of projects; it even calculates when you’re likely to complete your work, based on availability, vacations, and other tasks. You can manage team communication and time sheets too.

For product-design teams, a free app called Grabcad will keep, update, and share the latest version of a CAD project no matter where team members are. People can make annotations to those drawings using Skitch, also free. Slava Menn, CEO of Fortified Bike, uses both apps often to manage production of his Boston company’s bicycle products for urban commuters. “Instead of waiting for feedback from me for three to four days,” he says, “they can get it in three to four hours.”

Invoicing and accounting

Cloud software services make it easier to stay on top of finances via smartphone. Xero, which costs $19 to $70 a month, lets you link to your bank account, send invoices remotely, track cash flow, record assets, and check a loan balance. Xero works with 350 other apps, including those for handling inventory, job tracking, and point of sale. For $20 to $40 a month, rival FreshBooks focuses more on billing, letting you invoice from your phone, as well as track time, log expenses, and collaborate on projects. You can also log and approve expenses using Concur and integrate those transactions to QuickBooks for $8 per user per month.

Staying in touch

Some entrepreneurs find that it’s easier to set a standard app for companywide chats than to try to find people by phone, email, or text. Menn of Fortified Bike pays $2 per user each month for his seven employees and contractors to connect on HipChat, an app that allows them to chat no matter where they might be. (HipChat also has a free version.) There’s also Slack, which lets you hold group conversations, search messages and conversations, and share and access files from a dozen apps, including Google Docs, Twitter, and Dropbox. There’s a free version or, for $12.50 per user per month, you can upgrade for more security and archiving.

This story is from the April 1, 2015 issue of Fortune.