The links to various free/opensource programs most useful and interesting of April:
GooReader it allows you to read Google ebooks online and offline
EmailTray email notifications directly on your desktop, it supports many web mails
FeedDemon popular Windows feed reader
Yellaboo desktop app for all social networks
MailStore Home email backup software
Protected Folder password protect your folders
Undelete 360 recover accidentally deleted files
SaveGame Profiler make a backup of your save games profiles
SharkThief download music from groovshark.com service