Hacking is useful on it's own. In a world with omnipresence of the Matrix and technology, a technomancer or a decker in a party is a real God for many situations. Other answers cover how to multitask it, but I'd like to suggest another approach.
Hacking is a really big part of the rules and are often misunderstood by players and GMs. In my first games hacking took us almost 2 hours to figure out because the technomancer wanted to mess with the club's system and turn the group's tab to a "more reasonable price" (his words).
After this game session I had a discussion with the group and here's what we concluded. Note we're all programmers and such so we skipped the step 0 but if you and your group aren't familiar with the vocabulary of the Wireless world, start at step 0.
0. Learn what every words mean
Being familiar with what a node is and what's the use of a backdoor and macros is essential. It will not only improve your confidence at playing a hacker but also help you create interesting challenges for the group. I'm not suggesting completing a Computer science class but simply by familiarizing yourself with the meaning and the implication of those words will make things faster. It's like having a D&D Wizard who wouldn't know what the schools of magic do.
1. Know the mechanics...no seriously
This sounds like an obvious one, but wait a second. You have to learn them to a point where the GM can ask you what skills and softs are involved in creating a hidden backdoor, or a to overload a sentient personas. This is achievable by reading a lot and also practicing. Practicing, practicing. This sounds crazy because it's just a game but seriously, knowing this intimately will actually save you a lot of time. Between game sessions, create hacking challenges for your player and send them by email.
"You're in a cafe, trying to access the mall's network and mess with
the security system. You're objective is to get in, retrieve all admin
accounts, add one as a backdoor and put all surveillance systems in
loop. How do you proceed"
Just assume every skill check succeed..but ask the player to formulate the chain of skills he would use. Practice.
2. Use the quick method
By knowing the size of your pool for every basic actions will let you tell when to skip some rolls. By using the 4 dice => 1 auto success rule (it's all or nothing, no buying half and roll the rest), and knowing when to skip over simple actions like node access or cover your tracks will save you so much time. Some actions have fixed difficulty so why roll when you have a dice pool of 12 and you only need 2 success. Of course you might want to ask them to roll anyway for story purposes but for really routine actions (node access, gather intel, transfer file) you should skip them as long as their dice pool is big enough.
3. Read these
This forum post contains a PDF link to a step by step guide for hacking. Familiarizing yourself with it should be essential. http://forums.shadowrun4.com/index.php?topic=8388.msg149283#msg149283
The above has a step by step approach, this one is a complete list of actions a hacker can do with prerequisites and following steps. http://forums.shadowrun4.com/index.php?topic=5938.0
That's about it
The other answers cover the "make the hacking happen while something else happen for the group" but I think it's only half of the solution. The other half is to either house rule it (like you turn the whole process into a extended test with a frequency of 1 round for every core process) or to bite the bullet and play by the rules.