It's also worth noting that omnidirectional mics exhibit directionality at higher frequencies. Sometimes it's almost unnoticeable but sometimes it pays to make sure you aim (omnis) whenever possible. I recommend checking out John Eargle's The Microphone Book.

Does your phone have a earpiece jack?

Alternatively, you can use/setup a Skype account and then call in to your voicemail so you can playback on your computer. At that point you can then use an app like Audio Hijack to record directly to your computer or record from your soundcard/IO's outs ...

maybe a UPS or running a power balancer would help?

http://www.furmansound.com/product.php? ... d=IT-20_II
http://www.furmansound.com/product.php? ... PS-PFP_PRO

Goldpoint's SA4 is one input short:
http://www.goldpt.com/sa4.html

They also sell switches if you want to build your own without an attenuation knob.

small:
http://www.rdlnet.com/product.php?page=81

smaller:
http://www.rdlnet.com/product.php?page=86

For slide dobro, I like to pin/clip a mic to the player about 2-4 inches above instrument. This helps keep things steady for players that tend to stray from stand-mounted mics too.