Kudos to Google for offering upgraded storage plans for Picassa and Gmail (and coming soon to Google Documents et al).
When you reach the limit of free storage (i.e., 1GB for Picasa Web Albums, 2.8GB for Gmail), consider this your overflow solution. Plans start at $20/year for 6GB (yes, $5 cheaper than before), with larger plans ranging up to 250GB.
Plans range from $20/yr for 6 GB all the way up to 250 GB for $500/yr, and everywhere in between.
To sign up, visit your Google Account Page or follow this link.